PIA tools are command-line tools for manipulation with PIA image archives.PIA file format is used for storing a large number of image tiles in one file. PIA format is not an image format, it is a container format (similar to TAR, CPIO ... formats). It can contain arbitrary image types (usually PNG and JPEG). Images form a rectangular mesh, every stored image is indexed by coordinates. It is supposed that stored images have the same file format and dimensions. See PIA file format specification
Examples of PIA archives can be found here: SPOT satellite images of Europe
Program is written in C.