The software that creates and manages the photo galleries has included a bug that usually, but not always, incorrectly handles photo meta information- picture date, camera model, exposure, etc. As a result, the image date is often set to 01 January 1970 regardless of when the actual picture was taken. This makes it a little hard to sort galleries by date, the preferred method. I’ve implemented a fix of sorts that now gives newly added pictures the correct date but it didn’t fix the dates of the existing images. I could just upload all the pictures again but that’s a lot like work. I think I’ll just wait for a real bug fix from the developers that also retroactively fixes existing image dates. Should be soon. In the mean time, you’ll have to put up with oddly-organized photo galleries.
The “Recent Pictures” box over on the side bar should show you the most recently added pictures.