album is a free HTML/XHTML photo album and gallery generator that supports themes/skins. You can choose different themes or write your own to get different layouts and styles. It creates all your thumbnails (including directory thumbnails) and descends into directories so you can organize your photos. See the home page for more examples. album is also multi-lingual, with many languages being added all the time. N.B.: The purchase link is provided for donations; the software does not cost anything.
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.
ps2tiffs extracts the sampled images from a PostScript document. It is not a PostScript renderer. ps2tiffs is a system where the grazer feeds on the output of a PostScript interpreter whose image operators have been replaced by special data-hijacking functions. This has the benefit of allowing the extraction of images regardless of how they have been encoded, formatted, scaled, or squished by the app which generated the PostScript document. It outputs greyscale, RGB, and CMYK TIFFs.
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.