Great that you have managed to find a workaround for this.
Indeed Telerik Testing Framework has several methods for comparing images.
ArtOfTest.Common.CompareUtils.ImageCompare (Bitmap imageA, Bitmap imageB, Rectangle selectionArea, int tolerance)
- performs a compare of two images and returns whether they are the same within a specific tolerance. You can also define the area within the image to compare. It returns a bool value.
You can also use:
ArtOfTest.Common.CompareUtils.ImageExactCompare(Bitmap imageA, Bitmap imageB)
-It validates whether two images are exactly the same. Also returns a bool value.
Unfortunately there is no workaround for the .Source property issue.
All the best,
the Telerik team