Re: Gallery eating my battery...
Are all of your photos in Internal Storage, or on an external SD card? If there's a corrupt file somewhere, the Media Scanner might be hanging up on it, which uses battery. It usually shows up as Media Scanner in the Battery screen, but I wonder if it might have been folded into the Gallery app.
If your photos are on the external SD card, try unmounting and removing the SD card, and see if the battery drain persists.