Photoreal scenery design help neeed!

Ok, I'm in need of some help.
I just acquired a rather large satellite image of the Mt. Bachelor/ Three Sisters area and I would like to turn it into photorealistic terrain replacement textures.
Advice on how to do this, and where I could find the software (preferrably freeware) to accomplish the task would be greatly appreciated.
I just acquired a rather large satellite image of the Mt. Bachelor/ Three Sisters area and I would like to turn it into photorealistic terrain replacement textures.
Advice on how to do this, and where I could find the software (preferrably freeware) to accomplish the task would be greatly appreciated.