Image Alchemy has the ability to convert between over 90 different raster image formats (including all colorspace and compression variations of each format). Color management features include gamma correction, undercolour removal, seven high quality dithers, colorspace conversion, and palette manipulation. It also includes a Postscript interpreter.
pngquant is a batch conversion utility to quantize and dither truecolor PNG images, especially those with a full alpha channel, down to "RGBA-palette" PNGs (i.e., PLTE + tRNS in PNG parlance). 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 a simple command-line utilitiy to convert images from TIFF to PNG format. It is primarily useful in dealing with TIFF images that contain alpha channels (transparency information), since the NetPBM suite is (currently) ill-suited for such conversions. A few test images are included.
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.
The pnmtopng package contains the official pnmtopng and pngtopnm utilities for use with the rest of the PBMplus/NetPBM suite. They are among the best PNG-supporting applications available, with automatic detection of grayscale or palette images and excellent heuristics for creating the smallest possible PNG images.
pHoToMoLo is a toolset for managing JPEG images in JFIF or Exif format. Photomolo generates a static HTML 4.01- and CSS 1-based multi-resolution image gallery for a directory tree containing images. Exifiron losslessly compresses and corrects the orientation of Exif JPEG images. Jpegnail removes or embeds thumbnails. Jpegcom lets you edit embedded image comments using any text editor and image viewer. A shell script frontend for Exifiron is included for copying images from removable storage, such as USB or Compact Flash.
TAMOGEN is designed either to create a mosaic of one image out of another or to create a mosaic of one image out of itself. Instead of selecting images from a pool on a best-fit basis, the generator utilizes one user-identified image to create a mosaic of another user-identified image by altering the tone of the component image. TAMOGEN will create color or black-and-white mosaics of arbitrary size.