THese were made by me in paint by hand. If you dont like them, thats ok. But here they are.
32x32

64x64

I admit that im not to great of s spriter buy ill try and submit some good stuff. I can always change these to a differn't size or fix them. re the tiles supposed to be 64x64?
put tiles into GM from here to view each tile seperateley and see how they look:
32x32
http://img294.imageshack.us/img294/6236/stonetilesty1.gif
64x64
http://img181.imageshack.us/img181/651/biggerstonetileszm1.gif
Also you could always make them lighter or darker.