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).
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.
QCad is a powerful but easy to use 2D CAD program for Linux, Windows, and Mac OS X. It uses DXF as its standard file format. While other CAD packages are often rather complicated to use, QCad tries to stay comfortable, and even an absolute beginner can create professional drawings with a minimum of effort.
ResCafé is a Swing-based Java utility for reading and extracting resources such as ICONs and MENUs from the Resource Forks of Macintosh files. In particular, it allows Linux users to use nifty Mac-only icons with their favorite desktop, e.g., KDE. It is somewhat similar to ResEdit on MacOS except that it is not an editor; it operates on files in a read-only fashion. The various resource types are parsed by auto-detected plugin handler classes.
These are the demo programs that accompany O'Reilly's "PNG: The Definitive Guide." rpng is a simple file viewer with the ability to set a background color when displaying transparent PNGs. rpng2 is a progressive PNG viewer, designed to work like a web browser (though it contains no network code); it can generate a background image when displaying transparent PNGs. wpng is a simple converter from NetPBM to PNG format; in most respects it is much more limited than pnmtopng, but it supports interactive entry of PNG text annotations and will generate noninterlaced PNGs on the fly (rather than buffering the entire image first like pnmtopng). The viewers include simple front ends for both X and Win32; the converter is a command-line app that compiles on Unix, Windows, and probably other platforms.
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.
TransFig is a set of tools for creating TeX documents with graphics which are portable, in the sense that they can be printed in a wide variety of environments. The fig2dev program that is part of TransFig is used by xfig when exporting drawings to the various output formats such as PostScript (and EPS), CGM, JPEG, LaTeX, PNG, and more.
wApua is a WAP WML browser written in Perl with a Tk user interface. It uses libwww-perl as its backend, has history and cache, and can display most WML tags, including tables and WBMP images. It includes a WBMP to XBM (wbmp2xbm) converter for command line use. It runs under X11 on Linux, BSD, Solaris, and Mac OS X as well as on Windows (both native and under Cygwin with X11). It should also work on other operating systems which are supported by Perl 5.6 or higher and Tk 800 or higher.