Did any of you use Picasa?
I've never had any trouble with pics disappearing, even through rooting. I've had some thumbnails I CAN'T get rid of with the native Gallery app. All of them were resized in Picasa.
I cleaned out Picasa on the PC. There are no images there. Google still thinks there are.
These thumbnails cannot be seen by any app but the default Gallery. ES File manager doesn't see them, neither does Image Shrink or the replacement Gallery I just installed.
I think I worked with these pictures on another phone. When I got the Nexus, I only installed the pictures I wanted from the computer backup. I do not use Google backup. As soon as I put in Gmail account - there were the thumbnails. The Nexus was stock with GB when I got it, rooted it, re rooted with CM7.1 after ICS. Did CM 7.2, and now CM9. All of those installs said they were wiping phone. After root - just transferred pics again from computer, all well and good until I put in Gmail account. The damn thumbnails are back! So Picasa and Google have wires crossed somewhere. In fact, Dashboard on the PC insists there are photos in Picasa, but if you click on a link, there are no photos.
Gallery will also not recognize a rename of a file. I'll use ES File Manager to rename, but default Gallery will not see it.
Downloaded another version of Gallery from Play - it doesn't see the pics and let me delete the placeholders that showed up. Default Gallery is disabled.