Photos "disappear"
Unlike "Thaden" below, I do know (now) exactly what event causes all the photos to disappear from both the Camera Roll or Photo Library. At least I know one cause.
I completely cold-booted this iPhone 4 and the images reappeared. This happens now consistently.
It for sure can be reproduced be taking just one picture with the native Camera App. Do that (take a picture) and the EXIF IPTC MetaData Browser App can no longer "see" any images.
I am sure it is a simple fix. We just need a new release with that bug fixed. Come on, Cyril. I know you arent making a lot of $$ on this, but I also know you take pride in your work.
CG03026 about
Exif & IPTC Metadata Browser