This opens up directly to recent images, this is somewhat unintuitive and jarring- I wasn't sure I was in your app to get started, and didn't realize immediately I needed to select a photo.
I used one of your promo codes, thanks for this. I found the blur feature to be the most useful, I'd suggest making the free version of the app allow you to experiment with this feature. Maybe have the free version watermark images? Or limit the number of images you can save.
A walkthrough/intro screen to get started would go a long way.
Anyways, cool project, thanks for sharing