KVEC is a command line tool that allows you to convert raster graphics to vector graphics. KVEC is designed for 32 bit operating systems and runs on Win32, OS/2, HP-UX, NEXTSTEP, Linux, IRIX, AIX 4.x, Macintosh and BeOS. Docs are available in English and German. The shareware version is available for 30 day trial.
Macfork can be used to both list and extract resources from a Macintosh resource fork under unix. Currently it supports icon families, pict resources and palettes, but the data from any resource may be extracted to a data file. It was written to port Macintosh icons and pictures over to unix, but has many other potential uses.
Noptec Vector is an implementation of a bitmap vectorizing algorithm, specifically for creating background picture resources for the Sierra AGI interpreter. The program reads an image in BMP, PCX, or TGA format, converts it to 160 x 168 x 16 colors and writes the result in AGI readable format, optionally showing the result onscreen.
PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
pngcrush is an excellent batch-mode compression utility for PNG images. Depending on the application that created the original PNGs, it can improve the file size anywhere from a few percent to 40% or more (completely losslessly). The utility also allows specified PNG chunks (e.g. text comments) to be inserted or deleted, and it can fix incorrect gamma info written by Photoshop 5.0 as well as the erroneous iCCP chunk written by Photoshop 5.5.