This person describes the whole process he did to make a fantasy landscape. He blocked out the shapes for his idea, and then added some elements like a picture of a hiker, some landscapes, and textures them, and then lights, and adjusted his camera. He then goes over all the steps he did in photoshop which were straight forward. I'm sure you could use gimp or something like that also. Overall a very nice tutorial. The addition of photoshop really makes the image much nicer.