A simple GTK+1/2 painting program. mtPaint is designed for creating icons and pixel based artwork. It can edit indexed palette or 24 bit RGB images and offers basic painting and palette manipulation tools. Its main file format is PNG, although it can also handle JPEG, GIF, TIFF, BMP, XPM and XBM files. Due to its simplicity and lack of dependencies it runs well on GNU/Linux, Windows and older PC hardware.
If you have Gifsicle installed on your system you can use mtPaint to edit the frames of an animated GIF file. It is also possible to create animation frames by using the layer facilities, and then creating an animated GIF file using Gifsicle.