I wanted to put some sort of rainforest image on my free range cham room walls too, but doubting my art skills I tried another option. There are companies that make photo landscape murals for walls (you know, tropical beaches etc). I found one of a nice looking deciduous forest. They can be pasted like wallpaper, but I just tacked the panels up so I could move them easily. But, it was so realistic one of my chams kept trying to reach the trees in the "distance".