Some ID pictures work, others don't?

The identity upload picture only works with some graphics. Dimensions and file type seem to make little difference. Basically when you upload a new graphic it rarely refreshes, even after update, and certainly almosdt never remebers the graphics, even successfully used in the past. I have a 100 x 120 pixel jpeg which just refuses to load, but this is the case with many other valid graphic files.

I know this is similar to Oona's problem with Safari, but Bryan's response regarding updated uploader 2 months ago does not seem to have helped. Tested on IE7 and FF3.