Hi if I try to open the jpg at:
http://img163.imageshack.us/img163/2531/nnclogoscreen.jpg
and save as a png it will produce a corrupt png. It also seems to get into a loop on determining color depth before saving.
If I copy the image and paste it into a new picture I can use it fine.
I guess the original jpg has something wrong with it but would hope for some kind of error message or detecting the problem while producing the png.
Windows 7 x86 Paint.net 3.5.5.3767.28608
found a similar forum post here http://forums.getpaint.net/index.php?/topic/18707-damagedcorrupted-png-after-saving/
Thanks