Something Ive noticed just now, is that since photo albums are limited to Recently added / Recently deleted (unless you make your own), you can't easily share a photo if it's not in one of those folders. For example, if you try and share via twitter, i.e. via the twitter app, it only grants access to your recently added folder. Seemingly the only way you can add an older photo to Twitter is if you first find it in the photo album, and share it directly. Or am I missing something?