XPaint is an easy-to-use image editor which supports many standard and less standard paint procedures that demanding non-professional users would expect. It includes several advanced features like image processing algorithms, programmable C scripts, simultaneous editing of multiple images, and supports a wide variety of image formats.
SImg is a software for astronomical image processing. It contains a tool for visualization of highly dynamic images. The package consists of a library and applications which use it. Some of the features are deconvolution (various methods), Video4Linux support, PSF computation, approximation by linear combination of images and polynoms, various color transforms, automatic shifting of image sets (for addition and color composition), and more.
MultiSlice RTP is a radiotherapy treatment planning and medical image processing system developed for Silicon Graphics MIPS architecture systems and the IRIX operating system (5.3 and above). It allows you to manipulate upto 20 2D CT image slices as one 3D slice and run bulk batch processing algorithms on the images loaded. Written in C and linked against the MOTIF toolkit, it also runs on Xfree/Linux/Lesstif and can load RAW CT images from a CT scanner directly.
GridFlow is a plugin for PureData, Ruby, and jMax. It provides the ability to process images and video as N-dimensional arrays ("Grids"). It consists of a framework for grid transmissions, elementary grid processing objects, picture-oriented processing objects, and input/output objects. It also allows one to write plugins for PureData and jMax using the Ruby language.
Tux Paint is a simple and entertaining drawing program geared towards young children. It has a simple interface, sound effects, and a cartoon character (Tux, the Linux penguin). Along with drawing brush strokes, lines and shapes, you can also enter text and place "rubber stamp" (or "sticker") images on the picture. Tux Paint is extensible, and could be useful in an educational environment (such as a grammar, elementary, or grade school). It's portable across numerous platforms, and runs well even on slower systems like the Pentium 133MHz.
CinePaint is a deep paint image retouching tool that supports higher color fidelity than ordinary painting tools. CinePaint is used to retouch feature films and for professional photography. CinePaint opens high fidelity image file formats such as DPX, 16-bit TIFF, and OpenEXR, and conventional formats like JPEG and PNG. It has a flipbook for movie playback of image sequences in RAM. It supports 8-bit, 16-bit, and 32-bit color channels, HDR, and CMS.