Subtract with overflow in image.rs line 471

[dsherret]

Bug description

I get the following error:

thread 'main' panicked at V:\.cache\cargo\registry\src\index.crates.io-1949cf8c6b5b557f\editpe-0.2.1\src\image.rs:471:29:
attempt to subtract with overflow
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

I was investigating how to reproduce the issue in #1 and came across this bug.

Reproduction steps

1. Install Deno or alternatively run the steps manually in build.ts
2. git clone https://github.com/dsherret/editpe-bugs
3. git switch subtract_with_overflow_image_471
4. deno run -A build.ts