I hope to have a set of test images for the course soon. Some images are available now; some will have to wait until I can find another 100-200 Mbytes on our anonymous ftp server.
In a few days I hope to have 24 images from the Final Version 2.0 of the Kodak Photo CD Photo Sampler CD. For now, one can access certain files via anonymous ftp by clicking here ;I hope to have more information about how to access full-color versions of these files and how effective my wavelet code was in compressing these images.
Each image has 2048 rows of 3072 pixels; the .pgm files use one byte for each pixel, 0 is black, 255 is white. If you don't have software to read .pgm files, then just use the raw data-it's the last 2048x3072=6,291,456 bytes of each .pgm file.
The overviews are in .ppm format; each pixel is allocated three bytes for each of red, green, and blue. Again, if you don't have software to read this format, then just extract the raw data after the header information.
The FBI has an image compression standard for compressing digitized fingerprints; information on this standard can be found here. The images they give to illustrate their algorithm, together with some other information can be found here.
Various images from the USC image database can be found here. They can be used to test programs internally, but I'm not sure if they are identical to versions that are found in various image compression papers, so don't use them for that purpose.
Two large digitized mammograms that can be used for test purposes are found here. These are 12 bit/pixel images, scanned at 35 micron resolution; each pixel is stored in two bytes, least significant byte first, in David Clunie's 16 bit extension of .pgm format. Don't download these lightly, they are 25 and 32 megabytes in size.