graphics

pngcrush is an optimizer tool for PNG (Portable Network graphic) files. 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)

InkScape is an Open Source vector graphics editor, with capabilities similar to Illustrator, CorelDraw, or Xara X, using the W3C standard Scalable Vector Graphics (SVG) file format. Inkscape supports many advanced SVG features (markers, clones, alpha blending, etc.) and great care is taken in designing a streamlined interface.