Technical Enhancement to iOS App

This is not for a full project. Just a technical enhancement to an existing project. Currently, I have an App that takes 40 images of an animation and combines them and plays the full animation. What I need added is the technical ability to capture a photo (or pick from library) and allow the user to scale that photo inside an oval shape (for their head), and then apply this region to the same oval shaped head in all 40 images of the animation. This is so when the new animation is created, it will have the head of the person who took or chose a picture. Look at this app: [login to view URL] Notice how you are able to select an oval shaped region with a face. This is exactly how that should work. After you have that region, you just need to add it to all 40 images of the animation and re-create it (there's already a class included that creates an animation with a given set of images). So as long as you can get the selected region, generate 40 new images with this new oval shape by placing it on top of the 40 images of the animation, pass them through the already included class that combines images to make an animation, you'll have it done. I'm only looking for this technical enhancement, no special design or anything fancy. This functionality just has to work, however you're able to do it. If this works out well, I may decide to extend it with further enhancements, but for now this is the most important.