Hello,
I was adding images to a gallery today and noticed that some of my images weren't showing up in the image upload dialog. When I looked at file types I noticed it said "jpg,gif,png" the files in my picture folder were JPG with capital letters. The temporary solution was to change the extension to lowercase which is fine. I also don't know if this a browser/os specific bug as I use Linux and Firefox 3.5 or if the "allowed file extensions" is something that can be set in settings.
Thanks,
Brooke