Image annotation not showing on windows phone?

[objorke]

From oxyplot: oxyplot/oxyplot#965

Adding image annotation not showing on windows phone.

what i try :

OxyImage imageAdd;
            OxyImage imageDelete;

            var assembly = typeof(TssDashboard).GetTypeInfo().Assembly;
            //var str = this.GetType().AssemblyQualifiedName;
            using (var stream = assembly.GetManifestResourceStream("Test.Resources.OKLA.png"))
            {
                imageAdd = new OxyImage(stream);
            }
            using (var stream = assembly.GetManifestResourceStream("Test.Resources.DeleteLA.png"))
            {
                imageDelete = new OxyImage(stream);
            }
            //// Relative to plot area, above top/left corner, 20pt high
            model.Annotations.Add(new OxyPlot.Annotations.ImageAnnotation
            {
                ImageSource = imageAdd,
                X = new PlotLength(DateTimeAxis.ToDouble(DictVarData.ElementAt(DictVarData.Count -50 ).Name), PlotLengthUnit.Data),
                Y = new PlotLength(980, PlotLengthUnit.Data),
                Width= new PlotLength(44, PlotLengthUnit.ScreenUnits),
                HorizontalAlignment = OxyPlot.HorizontalAlignment.Center,
                VerticalAlignment = OxyPlot.VerticalAlignment.Top,
            });
model.InvalidatePlot(true);

code execution not showing image on chart.