Build a 'Pixel Art' Photo Editor App

I am seeking a basic photo-editor app to turn photos into pixel art. I am seeking the following features:
- Specialised in turning photos into 8-bit pixel artwork, see example - (https://giventofly.github.io/pixelit/).
- basic filters based on 8-bit / 16-bit art
- upload photo from phone to edit
- take photo from camera and edit
- ability to save image as JPEG/PNG
- save photos in an album on the phone

I like simple, clean colours and and design, with the above website showing a good example. There are additional features I am looking at developing in the future, however want to see how it goes on the market first.

I also want to own all of the source files so I can implement different logos etc once I have had them designed

Thank you for your time

JB