How to re-render the whatsthat image ?

1. I put low resolution height field and image maps, so that you basically just need to render whatsthat.pov with the options you like.

2. To re-render higher resolution maps and fields, you have to:
   - render sol_hf.pov (in png)
   - render essai_adv_texture.pov with variable fn set to 1 to a file called mur_hf.png
   - render essai_adv_texture.pov with variable fn set to 3 to a file called mur_pig.png
   - render whatsthat.pov again.