Ptpt

This app can import images up to 4096x4096px and you can create pixel art up to 999x999px.
You can resize your images, adjust image position, and adjust image tones.
When converting to pixel art, you can select a palette of up to 64 colors and automatically reduce the colors of the image to the palette colors.
You can set halftones to reduce the colors of the image, so you can easily create hand-drawn pixel art look.
You can also retouch the image with this app.
Images and palettes can export to your device as png images.
This app can also display pixel art as a handicraft pattern, and you can use this app to both create pixel art and create crafts.