This package contains a small, stand-alone ANSI C program I wrote for a limited, specific purpose: compressing 16-bit integer FITS images. It doesn't handle any other type of FITS image, and it doesn't work on machines with bytes ordered least-significant-byte first. But it does the job for me (and keeps the FITS header uncompressed!), so I'm happy to share it with others.
These programs are based upon algorithms probably created by Robert Rice and Pen-Shu Yeh, and definitely developed by Nan Ellman and Robert Lupton. Nan and Robert L. have created versions for use in dealing with Sloan Digital Sky Survey images. All the afore-mentioned did the hard part. All I did was to put the algorithms into practice.
You should probably look at the README file to make sure the program will meet your needs. A description of the program usage, and the algorithms within it, can be found in the Unix-style rice.1 man page. You'll probably prefer to browse the HTML version of man page.
Those interested in a very detailed description of the algorithm should read a paper describing the method (in Postscript format); it's unlikely this paper will ever by submitted to a journal, or published anywhere, so this is your only chance to see it. The paper includes a table showing the amount of compression achieved on a set of "standard" astronomical images; these are described in Murtaugh and Warmels, 1989, Proceedings of 1st ESO/ST-ECF Data Analysis Workshop, ed. P. J. Grosbol, F. Murtaugh, and R. H. Warmels, (Garching: ESO). You can grab your own copy of these test images at ftp://iraf.noao.edu/iraf/extern/focas.std.tar.Z.
Now, you can pick up the code in several ways, either by downloading each file separately, or by grabbing a "shar" format file and then un-packing it on your home machine. Just follow the instructions in the README file.