I really enjoyed learning about photo editing in class today. Mike is a great resource and a fun teacher. The most useful editing I learned from Mike is how to wireless beam from one iPad to another iPad. This is extremely useful for students working on a group project so that everyone in the group can work on the same project simultaneously.
Fotoflexer and Pixlr and Picmonkey are great tools. Especially like Pixlr at they have free apps which can edit similar to the webpage. Picmonkey advantage is the large amount of online editing backgrounds and pictures which are available and the ease of use of Picmonkey. This site is extremely user friendly, especially for people who are not tech savvy as this is a great point and click site.
There are many apps in which pics can be modified. I googled the 10 best free apps for photo editing on the move. Click on this link to get the search results. There are many lists of best apps for photo editing. To find the best apps for what your photo editing needs are, I would suggest reading the critic reviews descriptions to see if the features of the app are specific for your project.