This is just a suggestion. The selection rectangle is white so when selecting images which have been scanned on a white background, it's difficult to see the rectangle. Of course there will never be a colour that is appropriate for all images so I was wondering if marching ants could be implemented as an option please?
Marching ants or "xor" with underlying pixel color would work.
*** Bug 449082 has been marked as a duplicate of this bug. ***