Excuse the the big post as there is no spoiler option. Image resolution is automatically set by the app depending of the image size. It is usually at the highest resolution. There is no image options but you can resize an image. Here's how:
1.) open up a project (I'm using a example one)
2.) In this project the image is zoomed out (above), so when we save it it will be zoomed out with bad quality. To fix this: in the project, zoom in or out. What you see on your screen is what will appear in the saved image (below).
3.) save the image and it should appear how it is seen from the project view in the saved photo in your camera rol (below)l.
4.) how it looks without zooming in or out in the project when saved in camera roll (below).