Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
Percolator - Percolator: the always fun, supremely unique photo app that is sure to surprise you! FEATURES:
Pixilart - A drawing app for delightfully retro pixel art
Trigraphy - Photo editing app that allows you to make mosaic/abstract looking art.
Pixel Art Studio - A purpose-built drawing tool for pixel artists
WidsMob Montage - Make stunning mosaic photos or montage shape with tiles, which supports both JPEG and PNG files.