GroupMachine

A cross-platform command-line tool (Windows, Linux, macOS) for grouping photos and videos into albums (folders) based on time and location changes. It can also name these albums using real-world place names, making your collections more meaningful and easier to navigate.

📚 Overview

GroupMachine helps you organize large collections of photos and videos by grouping them into albums based on when and where they were taken. It’s especially useful if you’ve downloaded images from your camera, mobile phone or cloud service (like Apple iCloud or Google Photos), which often contain large, mixed sets from multiple locations and dates.

By default, the tool groups your photos and videos into albums - which are simply folders containing related media files. It creates a new album whenever there’s a noticeable gap in time or distance between your shots (for example, different cities or days apart). This way, the folder structure naturally reflects your trips, events, or outings without manual sorting.

Tip

Once you've grouped your photos, SideBySide can combine two portrait shots into a single landscape image, making them ready for digital frames without awkward cropping or black bars.

🧰 Features

• 💻 Runs on Windows 10 & 11, Linux (x64, ARM64, ARM32), and macOS (Intel & Apple Silicon)
• 🖼️ Groups downloaded photos and videos into albums based on time and location.
• 🧾 Uses photo and video metadata for the most accurate time and location (with fallback to file timestamps)
• ⏱️ Uses a configurable time gap (default: 48 hours) to define album boundaries.
• 📏 Uses a configurable distance gap (default: 50 km) to define album boundaries.
• ⏳ Supports date ranges, can ignore recent photos and can resume from last processed.
• 🗺️ Supports the GeoNames database to give album folders meaningful place names.
• 📍 Fills missing or invalid GPS data by inferring locations from nearby photos taken close in time.
• 🗓️ Enables appending of extra date text to the end of album names.
• 🏷️ Enables prefixing of extra text, including dates and creation of folder names.
• 🧠 Uses file hashing to detect identical files before renaming.
• 🧪 Simulation mode to preview changes without making any modifications.
• 🧮 Parallel processing speeds up hashing, metadata extraction, and file operations for large libraries.
• ✂️ Copies, moves or links files to new album folders.
• ⚙️ Automatic fallback to soft links when hard linking is not possible.
• 📘 Logs all actions, including skipped files, errors, and final summaries.

🧩 How does grouping work?

Grouping is based on two key factors: the time between shots and the distance between their locations. When the gap between consecutive photos or videos exceeds either the time or distance threshold, a new album is started.

Using the default thresholds (48 hours and 50 km) means that photos/videos taken less than 2 days apart and within 50 kilometres (or 31 miles) will be grouped together. For example, photos/videos taken during a single day trip or a weekend away will usually fall into the same album. If you then travel to a different city a few days later, that will create a new album. This approach is designed to reflect natural breaks in your timeline, capturing major location changes or extended time gaps.

Because the grouping relies on metadata timestamps and GPS coordinates, it assumes your media files include accurate time and location information. These assumptions generally hold true for photos and videos taken by modern smartphones and digital cameras. If the time metadata is missing or invalid, GroupMachine can use the created or last modified timestamp of the file instead (whichever is the earliest).

You can override these defaults using -t (--time) and -d (--distance). In regions where towns and landmarks are closer together (such as the UK, much of Europe, or Japan), a smaller distance like 25 km may produce more meaningful albums.

Note

Videos with embedded GPS data are not currently supported. Most consumer devices (including iPhones) do not store location metadata in videos, so location-based grouping only applies to photos. However, videos will still be included in albums based on time proximity - if they fall within the configured time threshold, they’ll be grouped alongside nearby photos.

🧭 Enhancing album names using location data

By default, album folders are named using date ranges reflecting when the photos or videos were taken. You can improve folder naming by using the GeoNames database, which maps GPS coordinates to nearby place names.

If you provide the GeoNames data, GroupMachine will look up the nearest populated place for each photo or video. It then selects up to four place names for the album title. These are chosen in the order they first appear in the group, with less frequent locations dropped if more than four are found. The result is a name that prioritises the most representative places, preserving the order of your journey.

For example, an album might be named "Paris, Le Marais, and Versailles" instead of just "5 Apr 2025 - 6 Apr 2025".

If you frequently visit the same places, you can avoid album name collisions by appending a date to each name using -a or --append. For instance, using --append "MMMM yyyy" would label your album as "Paris, Le Marais and Versailles (April 2025)"

To use this feature, download a GeoNames database file from here. You can choose allCountries.zip for global data or the .zip file for a specific country. A list of supported countries and datasets is available here. You'll then need to manually decompress the .zip file and pass the path and filename of the extracted .txt file to the program using -g or --geocode.

Location selection avoids overly narrow names. GroupMachine prioritises broader place names (e.g. "Paris") over exact landmarks (e.g. "Eiffel Tower"), so albums are grouped by larger, recognisable areas. You can adjust the level of detail with -p (--precision), choosing between broad (cities/districts), standard (neighbourhoods/villages), or precise (landmarks and points of interest).

Tip

If your photos span multiple countries, consider using the full allCountries.txt dataset for best results. It takes longer to load but ensures accurate results across borders.

For photos and videos with missing or invalid GPS data, GroupMachine can infer their location from the nearest photo or video taken close in time (imputing). In practice, this means it assumes you were at the same location as the closest previous or next item with valid GPS data. This helps group media without GPS coordinates with other items from the same event or trip, but the inferred location will not reflect actual movement between shots.

📦 Download

Get the latest version from https://github.com/mrsilver76/groupmachine/releases.

Each release includes the following files (x.x.x denotes the version number):

Platform	Download
Microsoft Windows 10 & 11	GroupMachine-x.x.x-win-x64.exe ✅ Most users should choose this
Linux (64-bit Intel/AMD)	GroupMachine-x.x.x-linux-x64
Linux (64-bit ARM), e.g. Pi 4 and newer	GroupMachine-x.x.x-linux-arm64
Linux (32-bit ARM), e.g. Pi 3 and older	GroupMachine-x.x.x-linux-arm
Docker, e.g. Synology NAS	GroupMachine-x.x.x-linux-x64
macOS (Apple Silicon)	GroupMachine-x.x.x-osx-arm64
macOS (Intel)	GroupMachine-x.x.x-osx-x64
Other/Developers	Source code (zip / tar.gz)

Tip

There is no installer for native platforms. Just download the appropriate file and run it from the command line. If you're using Docker (e.g. on Synology), setup will differ - see notes below.

macOS users

• Download the appropriate binary for your platform (see table above).
• Install the .NET 8.0 runtime. Slightly more technical information can be found here.
• ⚠️ Do not install the SDK, ASP.NET Core Runtime, or Desktop Runtime.
• Make the downloaded file executable: chmod +x GroupMachine-x.x.x-<your-platform>
• If you get zsh: killed when running the executable then:
  • Apply an ad-hoc code signature: codesign --force --deep --sign - GroupMachine-x.x.x-<your-platform>
  • Remove the quarantine attribute: xattr -d com.apple.quarantine GroupMachine-x.x.x-<your-platform>

Linux users

• Download the appropriate binary for your platform (see table above).
• Install the .NET 8.0 runtime. Slightly more technical pages can be found here.
• ⚠️ Do not install the SDK, ASP.NET Core Runtime, or Desktop Runtime.
• Make the downloaded file executable: chmod +x GroupMachine-x.x.x-<your-platform>

Docker users

• Install the .NET 8.0 Linux runtime inside the container or use a .NET container image.
• ⚠️ Do not install the SDK, ASP.NET Core Runtime, or Desktop Runtime.
• Use the GroupMachine-x.x.x-linux-x64 binary inside the container.
• Mount your photo folders into the container with appropriate read and write access.

Platform testing notes

• Tested extensively: Windows 11
• Tested moderately: Linux (64-bit ARM, Raspberry Pi 5 only)
• Not tested: Windows 10, Linux (x64), Linux (32-bit ARM), Docker, macOS (x64 & Apple Silicon)

Note

Docker and macOS environments have not been tested, and no platform-specific guidance is available as these setups are outside the developer’s experience. While GroupMachine should work fine on them, support will be limited to questions directly related to the tool itself.

🚀 Quick start guide

This is the simplest way to use GroupMachine. It scans d:\Photos (and all sub-folders) for photo/video content and moves it into dated subfolders within e:\My Album. It uses the default thresholds (48 hours and 50 km) and default date format (eg 20 Jul 2025).

GroupMachine "d:\Photos" -m -r -o "e:\My Album"

GroupMachine "d:\Photos" --move --recursive --output "e:\My Album"

This is a more complicated example that uses the GeoNames database (and the allCountries.txt) database file for naming folders and appends the four-digit year onto the album name. Files are copied instead of moved.

GroupMachine "d:\Photos" -o "e:\My Album" -r -g c:\temp\allCountries.txt -a "YYYY" -c

GroupMachine "d:\Photos" --output "e:\My Album" --recursive --geocode "c:\temp\allCountries.txt" --append "YYYY" --copy

This example shows how to change the thresholds (to 24 hours and 10 km), the date format of the folder names (to ISO-8601 format) and to skip looking for videos.

GroupMachine "d:\Photos" -r -o "e:\My Album" -t 24 -d 10 -f "yyyy-MM-dd" -nv -c

GroupMachine "d:\Photos" --recursive --output "e:\My Album" --time 24 --distance 10 --format "yyyy-MM-dd" --no-videos --copy

Tip

Use -s (--simulate) to preview how your albums will be grouped - no files are moved, copied or linked, so it’s a safe way to fine-tune all your settings before committing. To better understand what’s happening during processing, check the log file (the location is shown when you run -h or --help).

💻 Command line options

GroupMachine is a command-line tool. Run it from a terminal or command prompt, supplying all options and arguments directly on the command line. Logs with detailed information are also written and you can find the log file location using --help (-h).

GroupMachine [options] -o <destination folder> -m|-c|-l <source folder> [<source folder> ...]

Required

• -o <folder>, --output <folder>
  Specifies the destination folder for grouped albums. If the folder does not exist, it will be created automatically.

• <source folder> [<source folder> ...]
  One or more folders containing the photos and videos to be grouped.

• File copy mode (choose one of the following)
  One of these must be specified:

  • -c, --copy
    Copy files from the source folder to the destination folder.

  • -m, --move
    Move files from the source folder to the destination folder.

  • -l, --link
    Link files from the source folder to the destination folder. This avoids duplicating data by creating a reference to the original file instead of copying it.

    When used, GroupMachine first attempts to create a hard link, which behaves like a real file and doesn’t depend on the original path. If hard linking fails (e.g. across different drives), it falls back to creating a soft link (symbolic link), which points to the source file’s path and breaks if that file is moved or deleted.

Note

Files are never overwritten. If a file with the same name already exists in the destination, it is compared by content. If the files are not binary identical, a number is appended to the new file (e.g., IMG_1234 (2).jpg) to preserve both versions.

File selection

• -r, --recursive
  Recursively scan all subfolders within the specified source folders.

• -nv, --no-video
  Exclude videos (.mp4, .mov) from scanning.

• -np, --no-photo
  Exclude photos (.jpg, .jpeg) from scanning.

• -df <date>, --date-from <date>
  Include only files taken after this date. Files earlier than this date will be ignored. You must supply the date (and optional time) in ISO 8601 format: yyyy-mm-dd or yyyy-mm-dd hh:mm:ss. If you don't provide a time then midnight will be assumed.

Tip

You can also use the special value last to continue processing from the last file processed in a previous run. This is useful when you are incrementally grouping new photos without reprocessing everything.

• -dt <date>, --date-to <date>
  Include only files taken on or before this date. Files later than this date will be ignored. You must supply the date (and optional time) in ISO 8601 format: yyyy-mm-dd or yyyy-mm-dd hh:mm:ss. If you don't provide a time then midnight will be assumed.

Tip

You can also use the special value last to continue up to the last processed file from a previous run. This is useful when limiting processing to a specific time window or when resuming partial groupings.

• -xr (--exclude-recent)
  Exclude very recent files within the -t (--time) time threshold (default is 48 hours) when grouping into albums. This holds off processing new content until it’s clear that no additional photos or videos will be added to the same album.

  For example, imagine you take a series of photos in the evening. If you run GroupMachine immediately, it might create an album with just the first few photos. A couple of days later, running GroupMachine again would group the remaining photos from that evening into a new album, even though they logically belong with the album created on the previous run - since they were taken within the same -t (--time) timeframe. Using -xr (--exclude-recent) delays processing of the first set of files, ensuring that all photos are correctly grouped together in a single album once no further related content is expected.

Note

If you specify an end date and time with -dt (--date-to) that goes beyond the window required by -xr (--exclude-recent), the date and time will be adjusted forward to ensure that very recent files within the -t (--time) threshold are still ignored.

Grouping logic

• -d <number>, --distance <number>
  Distance threshold in kilometers. If two consecutive photos or videos are taken more than this distance apart, a new album is started. Set to 0 to disable distance-based grouping. If not supplied, the default is 50 km.

Tip

In regions with denser settlements (e.g. the UK, much of Europe, Japan), a smaller value such as 25 km may give more meaningful results.

• -t <number>, --time <number>
  Time threshold in hours. If two consecutive photos or videos are taken more than this many hours apart, a new album is started. Set to 0 to disable time-based grouping. If not supplied, the default is 48 hours.

Album naming

• -g <file>, --geocode <file>
  Full path to a GeoNames database file in .txt format. Providing this file enables automatic renaming of albums based on location data. You will need to manually decompress the .zip file provided by the GeoNames website before you can use it with GroupMachine.

Tip

For best performance, store the GeoNames database file on a local SSD. Loading it from a network share, USB drive, or HDD can be much slower.

• -f <format>, --format <format>
  Date format used for album folder names that use dates. This follows the .NET DateTime format syntax. The default is dd MMM yyyy (e.g., "20 Jul 2025"). Used when no GeoNames data is provided or no location can be determined.

• -p <number>, --precision <number>
  Defines how detailed the location names are when GroupMachine generates album titles. Lower numbers produces broader, more general album names (grouping photos by major cities or districts), while higher numbers produce more specific names (including neighborhoods, landmarks, and points of interest). The default is level 1 (broad).

  Level	Precision	Areas	Example
  1	Broad	Towns, cities & districts	Paris, Versailles
  2	Standard	As broad + villages & local areas	Le Marais, Montreuil
  3	Precise	As standard + spot features (see below)	Place des Vosges, Sainte-Chapelle

  Spot features are individual landmarks, buildings, or points of interest. Level 3 (precise) includes selected spot features that are typically relevant to tourist photography:

  • Cultural landmarks: castles, monuments, palaces, temples, mosques, churches, theatres, opera houses.
  • Historic and archaeological sites: ruins, tombs, pyramids, historical or archaeological sites.
  • Recognisable structures: towers, arches, caves, lighthouses, piers, quays, squares, gardens.
  • Public institutions and attractions: museums, zoos, famous universities, public libraries, stadiums.
  • Leisure and resort areas: marinas, resorts, golf courses, spas.
  • Religious or spiritual locations: missions, shrines.

  The list of spot features is fixed and cannot be changed.

• -a <format>, --append <format>
  Date format to append to album folder names that use locations. Useful to distinguish multiple visits to the same location. Dates are appended within brackets - e.g. using MMM yyyy will produce "Paris, Le Marais, and Versailles (Apr 2025)". Dates are defined using the .NET DateTime format syntax.

• -nr, --no-range
  Don't use a date range in album titles. By default, GroupMachine adds a date range (e.g. "12 Jun 2025 – 14 Jun 2025", using the format defined by -f, --format) when an album spans multiple days. With this option enabled, album names always use the date of the first item in the group, even if later items fall on different days.

• -np, --no-part
  Don't add part numbers to album titles. Normally, if multiple albums form on the same day, date range or in the same location (e.g. due to the distance threshold being exceeded), GroupMachine appends part numbers to distinguish them (e.g. "Paris (part 2)"). With this option enabled, part numbers are omitted and such groups are merged into a single album.

Tip

If you regularly visit the same locations at different times of the year and want to keep those visits separate, consider appending the date, month, or year to album names using the -a (--append) option.

• -pa <text>, --prefix-album <text>
  Adds custom text in front of each album folder name. If the text contains / (or \ on Windows), it is treated as part of the folder path, allowing you to create sub-folders. You can also include <...> placeholders using the .NET DateTime format syntax, which will expand based on the album’s date range.

Examples

Below are a few examples of using the prefix option to modify album names and/or create subfolders. In all cases, the album date is 5 April 2025. Examples marked with ⚠️ may produce unintended results, so pay special attention to them.

Command	Without GeoNames	With GeoNames	Notes
-pa "Trip to "	Trip to 5 Apr 2025 - 6 Apr 2025	Trip to Paris, Le Marais, and Versailles	Prefix every album.
-pa "Weekend in"	Weekend in5 Apr 2025 - 6 Apr 2025	Weekend inParis, Le Marais, and Versailles	⚠️ Missing trailing space causes run-on names!
-pa "<yyyy>/"	2025/5 Apr 2025 - 6 Apr 2025	2025/Paris, Le Marais, and Versailles	Creates a year subfolder.
-pa "<yyyy>/<MM>_"	2025/04_5 Apr 2025 - 6 Apr 2025	2025/04_Paris, Le Marais, and Versailles	As above, but also month prefix on album name.
-pa "Year <yyyy>/<MMMM>/"	Year 2025/April/5 Apr 2025 - 6 Apr 2025	Year 2025/April/Paris, Le Marais, and Versailles	Deeper nesting folders.
-pa "<yyyy>\<MMM>- "	2025\Apr- 5 Apr 2025 - 6 Apr 2025	2025\Apr- Paris, Le Marais, and Versailles	Windows path seperator also supported.
-pa "<yyyy>"	20255 Apr 2025 - 6 Apr 2025	2025Paris, Le Marais, and Versailles	⚠️ No trailing / or / means prefix not folder.

Caution

• If you don’t include a trailing space in your prefix, the album name will run directly after your text.
• If you are creating sub-folders, the prefix must end with / (or \ on Windows) otherwise the text will be added to the folder name instead of making a new folder.

• -u, --unique
  Always create new, unique albums. By default (and when using locations), GroupMachine may place photos into an existing folder if the album name matches. This can cause conflicts if you have two albums with the same name taken at different times. Using -u (--unique) forces a new folder to be created on each run. New folders use the same name with a numeric suffix such as (1), (2), and so on.

  You can also use -pa (--prefix-album) and/or -a (--append) to change the album name by adding extra text. Both options can make an album title unique without relying on numeric suffixes.

Others

• -nc, --no-check
  Disables GitHub version checks for GroupMachine.

Note

Version checks occur at most once every 7 days. GroupMachine connects only to this URL to retrieve version information. No data about you or your photo/video library is shared with the author or GitHub - you can verify this yourself by reviewing GitHubVersionChecker.cs

• -s, --simulate
  Runs all processing steps but does not copy, move or link any files. Ideal for testing and previewing changes.

• -ha <type>, --hash-algo <type>
  Select the hashing algorithm for duplicate detection. By default, GroupMachine uses CRC64-ECMA-FAST, a very fast 64-bit checksum that reads only the first 64 KiB of each file. This is extremely efficient for spotting duplicates in large collections. You can override this with:

  • md5 - Well-known and widely supported. Reads the entire file, so it is slower than CRC64-ECMA-FAST, but more accurate for full-file deduplication.
  • sha - Strong cryptographic hash. Slowest option, but provides maximum certainty when comparing full files. GroupMachine automatically chooses SHA256 on 32-bit systems and SHA512 on 64-bit systems.

• -mp <number>, --max-parallel <number>
  Controls how many files are processed at the same time during copying, moving, or linking. By default, GroupMachine automatically chooses a safe number of parallel tasks based on your CPU and storage type. If you experience crashes, performance or stability issues, try reducing the number of parallel tasks. Use -h (--help) to see the default value for your system.

• /?. -h, --help
  Displays the full help text with all available options, credits and the location of the log files.

DateTime format syntax

The -f (--format), -a (--append) and -pa (--prefix-album) options accept date formats using the .NET DateTime format syntax, allowing you to customize how dates appear. Below is a list of commonly used date formats for your reference:

Format String	Description	Example Output
dd MMM yyyy	Day (two digits) Month abbrev. Year (four digits)	20 Jul 2025
dd MMMM yyyy	Day (two digits) Full month name Year (four digits)	20 July 2025
MM/dd/yyyy	Month/day/year (common US format)	07/20/2025
dd/MM/yyyy	Day/month/year (common UK format)	20/07/2025
yyyy-MM-dd	ISO 8601 format (sortable)	2025-07-20
MMMM yyyy	Full month name and year	July 2025
MMM yyyy	Abbreviated month name and year	Jul 2025
yyyy	Year only	2025
dd-MM-yyyy	Day-month-year with dashes	20-07-2025

For more detailed information, please refer to this page authored by Microsoft.

🔄 Automating downloads and album creation

You can run GroupMachine manually on any folder of photos/videos whenever you like. This is quick, flexible, and works well if you prefer to organise albums on demand.

However, for those who want more automation, you can also create a workflow that automatically downloads new photos from your cloud service (for example, iCloud or Google Photos) and then groups them into albums using GroupMachine. This allows you to maintain an organized library without manually moving files each time.

Key points for setting up an automated workflow:

• Automate downloads – Use a third-party tool to fetch images from your cloud service. For example, iCloud Photos Downloader can download photos and videos from iCloud. There are probably similar tools for Google Photos or other services.
• Unsupported HEIC images from Apple devices – Photos in HEIC format (with the extension .heic) are not supported by GroupMachine. To automate conversion, use something like ImageMagick (e.g., magick.exe IMG_001.heic IMG_001.jpg), after which GroupMachine can process the JPEG normally. Apple devices never generate a JPG with the same filename as a HEIC, so conversion won’t overwrite existing files.
• Process only new files – Use -df last (--date-from last) to tell GroupMachine to only process files added since the last run. This prevents reprocessing older files and ensures incremental grouping.
• Access the last processed date – If you need to incorporate further scripting, the last date processed is stored in settings.ini. You can locate this file by checking the path displayed when you run -h (--help), usually in the parent folder to the log files.
• Avoid premature album creation – Include -xr (--exclude-recent) to hold off processing very recent photos. This ensures that files still likely to belong to the same album aren’t split across runs.
• Organize album names – Use -pa (--prefix-album) to place albums into folders (for example, by year) or -a (--append) to add date elements to the album name (such as year or month). This prevents multiple visits to the same location from merging into a single folder and keeps your albums clear and chronological.
• Save disk space – If you plan to keep all downloaded photos, consider using -l (--link) instead of copy or move. This creates links to the original files without duplicating them.
• Keep geocode data current – If you’re using location-based album naming, update your GeoNames database periodically to ensure accurate place names.
• Integrate into Immich – If you host your photos and videos with Immich, use Immich Folder Album Creator to automatically turn the folders created by GroupMachine into albums within Immich.
• Use with other software – Picasa (Google’s legacy desktop app), as well as tools like PhotoPrism, LibrePhotos, Photoview, and digiKam, detect and display albums based on your folder structure, making them compatible with GroupMachine’s output. Synology Photos, however, doesn’t currently offer a way to auto-generate albums from newly added folders or files.

Tip

A simple workflow could be a daily or weekly script that downloads new images, then runs GroupMachine with -df last -xr -pa "<yyyy>/" to incrementally organize new content into neatly named, chronological albums.

🛟 Questions/problems?

Please raise an issue at https://github.com/mrsilver76/groupmachine/issues.

💡 Future development: open but unplanned

GroupMachine currently meets the needs it was designed for, and no major new features are planned at this time. However, the project remains open to community suggestions and improvements. If you have ideas or see ways to enhance the tool, please feel free to submit a feature request.

📝 Attribution

• Gallery icons by Freepik - Flaticon (https://www.flaticon.com/free-icons/gallery)
• Apple and iCloud are trademarks of Apple Inc., registered in the U.S. and other countries. This tool is not affiliated with or endorsed by Apple Inc.
• Google and Google Photos are trademarks of Google LLC. This tool is not affiliated with or endorsed by Google LLC.
• .NET is a trademark of Microsoft Corporation. This tool is developed using the .NET platform but is not affiliated with or endorsed by Microsoft.
• GeoNames is a project of Unxos GmbH. This tool is not affiliated with or endorsed by Unxos GmbH.

🕰️ Version history

1.3.0 (08 October 2025)

• Replaced -p (--precise) with new -p (--precision) to support three levels of album naming detail.
• Added progress bar for long running tasks; displays percentage complete and estimated time left.
• Updated GPL copyright version in comments to correctly reflect GNU GPL v2 (or later).
• Updated documentation.

1.2.0 (22 September 2025)

• Improved grouping by filling missing/invalid GPS data (imputing) with locations inferred from photos taken close in time.
• Moved content sorting by date earlier in the process to support imputing and improve debugging with logs.
• Added automatic detection of a safe number of parallel tasks based on CPU and storage type to prevent SEHException crashes on network drives.
• Added -mp (--max-parallel) option to allow users to override the default number of parallel copy, move, or link operations.
• Default hashing switched to CRC64-ECMA-FAST (64 KiB prefix) for much faster performance; accidental collisions remain rare.
• Added -ha (--hash-algo) to override the hashing algorithm with MD5 or SHA512 (SHA256 on 32-bit systems).
• Added file size comparison before hashing to further improve duplicate-checking speed.
• Fixed a bug where the last processed timestamp would be incorrectly updated to an earlier date.
• Tidied up logging and removed superfluous entries.
• Fixed a bug where the version checker formatted version numbers using .NET conventions instead of semantic versioning.
• Updated publishing powershell script to avoid hanging after first build has been completed.

1.1.0 (12 September 2025)

• Added -df (--date-from) and -dt (--date-to) to define the photo date range.
• Added support for using last with both -df and -dt, allowing resuming of previous runs.
• Added -xr (--exclude-recent) to skip photos that would appear in future albums (using -t threshold).
• Added -p (--prepend) to prefix folder names; supports date formats and folder creation.
• Added -nc (--no-check) to disable GitHub version checking.
• Files with no location data are counted to highlight potential issues.
• New header displays all key configuration information.
• Added -u (--unique) to prevent existing album folders from being re-used when album names clash.
• Improved logger performance by keeping files open instead of repeatedly opening/closing.
• Split utility functions into static classes for clearer structure.
• Resolved all .NET code analysis warnings to standardize style and tidy the codebase.
• Added documentation on how GroupMachine can be used in an automated workflow.

1.0.0 (08 August 2025)

• 🏁 Declared as the first stable release.
• Enforced use of -c (--copy), -m (--move), or -l (--link) to specify the copy mode.
• Added -l (--link) option for hard linking, falling back to soft links on failure.
• Added -p (--precise) to enable precise location names (e.g. stations, parks, landmarks, etc.) in album titles.
• Added -nr (--no-range) to show only the first date in folder names that span multiple days.
• Added -np (--no-part) to suppress part number suffixes.
• Changed album title logic: dropped popularity sorting; locations now kept in time order with the least-used removed.
• Updated -s (--simulate) to show the destination folder structure.
• Refactored the "(part x)" numbering logic to ignore existing folders on disk, relying on date suffixes for uniqueness.
• Switched to SHA512 for identical file checks on 64-bit processors, 32-bit processors continue to use SHA256.
• Removed -u (--unique) check due to poor performance and limited value.
• Logger now includes OS details to assist with debugging.
• Re-ordered command-line arguments and grouped them into logical sections.
• Cleaned up various pieces of code (analyzer suggestions regarding naming, simplifications, and style)

0.9.0 (22 July 2025)

• Initial release.