Found an annoying issue with the Gallery thumbnails on my Nexus. Selecting a thumbnail in the Gallery app wouldn’t display the right image. It seemed like it was 4 or 5 images “off”. This behavior was also apparent when selecting things like Wallpapers from the Gallery.
The fix was to delete/rebuild the thumbnail cache for the Gallery. Go into Astro file manager or similar and delete the cache files in /Android/data/com.google.android.gallery3d/cache/imgcache (3 of them), and reboot the device. Next time you view your Gallery, you will see the thumbnail images being regenerated.