Untar the package file to your GIMP directory: $ cd ~/.gimp-1.2/ $ gunzip -c /path/to/pmosaic-0.1.tar.gz | tar xf - The software will be extracted to the 'plug-ins' directory. Start GIMP. You should see two new options on the Xtns/Perl-Fu menu of the main toolbox. photomean and pmosaic Although these are provided in the GIMP's menu system it is recommended for performance reasons that they be run from the command-line or in batch. See the in-line documentation for full details. Before using the photomosaic software please run at least the pmosaic.t and photomean.t tests to verify correct installation and functionality. These can be found in the t/ directory from wherever you untarred the package. $ cd plug-ins/t $ perl ./photomean.t $ perl ./pmosaic.t If everything passes you are all set! For best results, the more photos in your library the better. I recommend around 4000 at an absolute minimum. 7-8000 should be adequate. If you create any really nice photomosaics with this software email the author and I'll consider adding them to the pmosaic home page at http://thebigmachine.org/gimp/pmosaic/ Happy Mosaicking!