pngquant | PNG (Portable Network Graphics) image optimising utility | Mehr ... |
pngquant is a command-line conversion utility to quantize and dither truecolor PNG images, especially those with a full alpha channel, down to 8-bit (or smaller) RGBA-palette PNGs. Such images are usually two to four times smaller than the full 32-bit versions, and partial transparency is preserved quite nicely. This makes pngquant especially useful both for Web sites and for PlayStation 2 development, where one of the texture formats is RGBA-palette-based (though not PNG-compressed). This is the same technique used for many of the images on the Miscellaneous Transparent PNGs page (http://www.libpng.org/pub/png/pngs-img.html), and the results are often indistinguishable from the original, truecolor PNG images. . Optimizers (like pngcrush and optipng) optimize the compression, usually losslessly, while pngquant quantizes colors down to 256 (or fewer) distinct RGBA combinations, which is lossy. |