A free program for Android, by Color by Number: Pixel Art by Peaksel.
Pixel Art: Color by Number is an application that allows you to create pixel art designs by coloring numbers. The number of colors and the design of the image are both customizable.
You can choose from over 600 images to paint and color, including lots of free images. The images can be categorized into a number of different categories, including animals, people, food, and sports.
Once you’ve chosen an image to paint, you can use different tools to help you in the process. These tools allow you to zoom in and out, and they also let you use different backgrounds, filters, and effects to create your own unique designs.
You can also use the app to create your own pixel art designs and share them with other people. The app has its own social networking component that lets you share your designs with other people.