You already know Instagram, which allows you to transform photos with editing tools and filters and to easily share them. Here are four more cool apps for photo hounds.
Pic Stitch. Create photo collages from hundreds of design options.
Snapchat. Send friends photo messages that last 10 seconds (not an embarrassing eternity).
Pixlr Express. Touch up photos like a pro in one simple app.
Capsule. Aggregate event photos for albums when guests use a hashtag to share snapshots.