My go-to apps are Snapseed which is the one I recommend if you only have one app, Hipstamatic for black and white street photography and for experimenting, Stackables app for texture and formulas that are easy to edit, and Superimpose for tweaking two edits. But all these apps have been discussed by others, so I thought I would elucidate on my five favorite less-known apps. All images ©Karen Axelrad   Dianaphoto For random double-exposures which are then enhanced with various filters. Scroll through your camera roll for an accidental coupling then lock one or both photos and try various filters out. The results are fun and surprising. I also save…