This could be done with those images too... easily

http://cgtextures.com/index.php?catid=10252

Note: All images could be used for Free and Commercial Projects if the images you want are edited (scaled / alpha channel / color adjust or what ever)

cYa Sebastian

Tutorials:
[Blender]Terrain creation ENG/GER
[Blender]Low Poly Tree Modeling
[GIMP]Create a Texture for Terrains
CLICK HERE