Snapseed The options this photo app gives you are perfect and give you lots of creative control over your photos, but I found it a bit confusing at first. More clear controls would do this great app justice.
Pixlr-o-matic Another vintage filter app filled with nostalgic goodness. Easy to use and with good quality filters!
Photo Stats – infographic creator for your iPhone photos This cool app pulls data from your existing photo library to tell you where and when you've been snapping your photos. Beautifully composed, this is a fun app especially if you have a large collection of photos from your travels!