WidsMob Montage is able to make mosaic and montage photographs. You can also adjust different parameters, apply frames and effects to make stunning photo mosaic. It create montage files in excellent quality from tiles in both JPEG and PNG.
Command line based Python based mosaic generator
Free and open source image mosaic program for your Mac
Free Java tool for creating accurate photomosaics
Cross-platform application to create a photo mosaic, using pictures from Flickr, Facebook, or local files
Free application that allows you to create mosaic images
Fill your screen with many types of media files and view them as a mosaic