Maxima Studio –Texture collection 'Grounds' wich has nine themes:
Earth, Flowers, Grass, Leafs, Asphalt, Cement. Sand, Stones, Tiles .
“Tiles” theme have 23 files with bump map and some of them with opacity map in resolution 1024x768 pixels.
All the pictures are JPEG compressed at high quality in 24 bits (16 milion colors).
The provided opacity map is ideal for making multi-layered materials