I'm guessing that the thumb isn't square and when it resamples, that it keeps it proportionate and one falls outside the limits each time--either too small or too large. I'm not sure what you mean by 'save thumbnail' in PS since I don't use it--wave the thumb and then browse to its file. Save a .jpeg that has 200 x 200 dimensions and is less than 15kb (I think) in size. Check both dimensions--I just uploaded a thumb w/o any problems. However, I do remember getting that message when one of my dimensions was several pixels over 200--like 204. Diane