Flickr

No matter how you feel about the venerable Web service's redesign earlier this year, Flickr's app is an undeniably simple and wonderful tool for photo sharing. Along with interacting easily with the Flickr mothership on the Web, the app has an excellent collection of live filters, solid photo-editing tools to enhance, straighten, and tweak shots, and ways to share your photo masterpieces with other social networks including Tumblr, FacebookPinterest, and Twitter. Plus, you get an unprecedented free terabyte of storage, which is more than any other photo-sharing service offers. [Free; Android, iOS, and Windows]