Open Source C Graphics Software

Tux Paint is a free, award-winning drawing program originally created for children ages 3 to 12, but enjoyed by all! It combines an easy-to-use interface, fun sound effects, and an encouraging cartoon mascot who guides children as they use the program. You're presented with a blank canvas and a variety of drawing tools to help them be creative. Along with paintbrush, shapes and text, Tux Paint includes a "stamp" feature to add pre-drawn or photographic imagery to pictures, and a set of "magic tools" that provide filter effects (like blur, tint and waves) and interesting drawing tools (like train tracks, bubbles and grass). Tux Paint includes a collection of "starter" images, both coloring-book style and photo-realistic, and a large collections of stamps are available as a separate download. Additional content can be added by parents & teachers, or downloaded from 3rd parties. Tux Paint is available for Windows, macOS, Android, Linux, & Haiku operating systems, among others.

Dia Diagram Editor is free Open Source drawing software for Windows, Mac OS X and Linux. Dia supports more than 30 different diagram types like flowcharts, network diagrams, database models. More than a thousand readymade objects help to draw professional diagrams. Dia can read and write a number of different raster and vector image formats. Software developers and database specialists can use Dia as a CASE tool to generate code skeletons from their drawings. Dia can be scripted and extended using Python.

gPhoto is a program and library framework that lets users download pictures from their digital cameras. The libgphoto2 library gives you access to hundreds of models of digital cameras on several platforms. GIT repo and Issue tracker lives at https://github.com/gphoto/ these days.

Collection of plugins for The GIMP.