With Loupe (free) you can group photos into a shape--this has potential for students to demonstrate knowledge on specific topic. You can enter text as well.
Upload photos, record voice and share...free. Again, I see potential for publishing--could have book reviews, commentary and more on classroom webpage.
Masher is free--can combine digital audio, video, text (yours and Masher's) to produce videos. Kids very muck like mashing--you need to encourage attributions, however.