aseprite

Aseprite is a program to create animated sprites. Its main features are:

      - Sprites are composed by layers & frames (as separated concepts).
      - Supported color modes: RGBA, Indexed (palettes up to 256 colors), and Grayscale.
      - Load/save sequence of PNG files and GIF animations (and FLC, FLI, JPG, BMP, PCX, TGA).
      - Export/import animations to/from Sprite Sheets.
      - Tiled drawing mode, useful to draw patterns and textures.
      - Undo/Redo for every operation.
      - Real-time animation preview.
      - Multiple editors support.
      - Pixel-art specific tools like filled Contour, Polygon, Shading mode, etc.
      - Onion skinning.

    This version is not redistributable: https://dev.aseprite.org/2016/09/01/new-source-code-license/
    Consider supporting the developer: https://aseprite.org/#buy