From one of my graduate students:
I used a very easy app called 30hands. In the app, I just save and upload the pictures from my camera roll. There is an option to record your voice over each slide/picture. At the end, you simply save it to the camera roll as a complete video. I use this often in my class. They can complete an entire project in one class period with this app. Also, since it is on their camera roll, students can immediately upload it to my school website/app- schoology. From there, I can play them for the class to see.
https://itunes.apple.com/us/app/30hands-create-show-what-you/id605013231?mt=8
BroadyEdTech 