Pixi image editor. Common features like: layers, im/export bmp/png/jpg/tga/tiff, scripted command interface, alpha, layers are worked on as floating points. Written using freepascal, and a work in progress. Modular design. Latest source in HG.
Whyteboard is a painting whiteboard application for Linux and Windows, that allows the annotation of PDF and PostScript documents, and image files with common drawing tools.