Adobe Photoshop Lightroom (Free) This pro-level photo editing app lets you process large groups of photos by creating a custom combination of image adjustments and applying them in a batch.
Union ($1.99) Readers enjoy this image blending tool for its ease of use and pro capabilities. Use the magic wand or brush tools to merge images into a new scene.
Timehop (Free) Our Throwback Thursday fans say Timehop makes their “hearts happy,” bringing a little charm of the past to the every day by sharing photos and status updates from years past.
Video Rotate & Flip (Free) Did you know that when you use the Camera app to record video, you can't rotate the orientation after the fact? Use this app to fix all those sideways videos.
Snapseed (Free) Readers chose Snapseed as the best allaround photo editor on the App Store. A standout feature is its large selection of filters, from double exposures to soft glow portraits.
Juxtaposer ($2.99) If you want to amuse your friends with hilarious photo compilations (e.g., a construction worker drilling into a human-sized bar of chocolate), Juxtaposer is the way to go.