Ok - more investigation confirms your suspicion. The image is large on disk and GDI+ is unable to open it (OOM exception), although the size is a reasonable 4000x6000. When I save over the image using 100% quality with irfanview, GDI+ is able to open it again. The only big difference between the saves is the number of unique colors is cut roughly in half; the size in memory is the same. There could be other things going on, but I don't know enough about imaging to know.
I suspect this is just GDI+ and its bad error messages. If you would like one of the images to investigate, I can send one but don't want to waste your time with a GDI+ issue. False alarm, but thanks for the discussion.
I suspect this is just GDI+ and its bad error messages. If you would like one of the images to investigate, I can send one but don't want to waste your time with a GDI+ issue. False alarm, but thanks for the discussion.