mtPaint (short for Mark Tyler's Painting Program) is a free and open-source raster graphics editor for creating icons, pixel art and for photo editing. It is available for Microsoft Windows and Linux operating systems. History mtPaint was originally written by Mark Tyler specifically for Linux operating systems, as a personal project for his own use. He evaluated existing graphics editors, but decided to write his own from scratch. Work was started on 7 August 2004 and the first public release was made on 13 September 2004. Of the development speed, Tyler noted, "This rapid development was only possible after I used and studied an excellent program call mhWaveEdit, written by Magnus Hjorth, in the Spring of 2004. As well as being an extremely good wave editing program, I also learnt many valuable lessons from this program." One of the design aims was to produce a lightweight graphics editors that could be run on older hardware. As such the interface uses the GTK 1/2 toolkit. Other design goals included that it be fast, reliable and free software under the GNU General Public License to protect user freedom. The first release was version 0.23 and it featured an indexed palette system, but no RGB support. Following version 0.30 the program was ported to Microsoft Windows as Tyler personally wanted to use it on a Windows computer he had. The version number went directly from release 0.97 to 2.00, with no 1.00 series. Version 2.00 was released on 7 August 2005. Tyler explained the version numbering, "To go from version 0.97 to 1.00 would not have reflected the quantum leap in functionality due to the implementation of layer facilities." Version 3.00 introduced channels with help from Dmitry Groshev, who did the work to implement the alpha (transparency), selection and mask channels. Groshev's coding was the first time that another developer's work had been directly written for mtPaint, although open source code from other projects had been incorporated previously. Version 3.00 also marked the start of a user manual for the program. Following 3.00 Tyler decided to leave the mtPaint and work on other software projects and Groshev became the maintainer. He continued to slowly add features and functionality, but through a slow cycle of releases. Version 3.50 was released on 31 December 2020 and is the most recent release. mtPaint has been included as a default application with a number of Linux distributions,