Aseprite

Aseprite is a pixel art and animation tool for creating 2D sprites, retro-style graphics, and animations. It offers features such as onion skinning, tiled mode, custom brushes, and a command-line interface for automation.

The software is designed for artists, game developers, and animators who work with pixel art. It supports various file formats, including its native .aseprite format, as well as GIF, PNG, and JPG.