I think there shouldn't be a limit, especially for NDS games seeing as most screenshots tend to give you a look at both screens. Since they are being looked at beforehand anyway, removing the size limit wouldn't be much of a problem.
The current size limit is 100kb, I won't remove it because people could just upload enourmous files and satuate our connection more easily. I can increase it a little though; what's the largest screenshot you've had so far?
By size I mean the dimensions of the image. Mine showed both top and bottom screen so it may have been taller than the restrictions. :x
no the restrictions for NDS screenshots are for both top and bottom, you have to use an emulator that doesn't save with borders between the top and bottom though. Programmatically it's too much of a bother to take care of every case, so we went with the one we liked the most.