Please respect the time and efforts of those who have written these messages. The copyright status of these messages is unclear at this time. Sometimes you can find them at good will extra tiles that people made mug holders with. I know of a glass place in the LA area that sells mosaic glass bits. I got some when I had my house fixed and asked for the extra carpeting and tiles.
Contractors sometimes have extras too.
You can have a photo put on tiles, which you can then have framed. I did find a few sites that had marble tiles, but they seemed to be primarily for flooring, and I don't remember enough about stone mosaic to know if these are thick enough for use as small pieces. A fellow by the name of Padruig, here in Northshield, does mosaics on occassion and his method of obtaining small pieces from larger ones is to put them in a sturdy cloth bag and whack away at them with a hammer on concrete. You don't get exactly sized pieces, but if you are careful and pull out desirable pieces after every few whacks, you get a good proportion of useable pieces with little waste. Thanks for the ideas on tiles, Mercy.