Help with creating raw land map file

Hello, everyone. Ive been trying to locate a program that can convert an image into a raw file that can be used to create an island. I have a specific shape and look that i wish to get but not sure what to do to get it. Im trying to create my own island based on the shape and look of a dragon picture that I have and wish it to be as detailed as possible so that it will show up as exactly what it is when in map view in SL. If you have any suggestions or tips, I would appreciate anything you can throw at me. Ive downloaded and installed two programs that I found mentioned in these forums: Terragen and Terrain Generator. If anyone has tips on how to work with these, I would also appreciate the assistance. My vision is to have mountainous, flat and rocky areas in the terrain as well as some highs areas allowing for caverns and underground hot springs. Some of this I know will have to be done manually on the land itself in game but Im hoping to reduce a good amount of the work by using a program first. Thanks in advance.

You may want to read up on this first.

http://secondlife.com/knowledgebase/article.php?id=288

A 3D terrain editor isn't really necessary unless you want to visualize it.
Most of the work can be done in Photoshop using the RAW format.

That's the thing, it is pretty hard to visualize how the land will look if you're just using Photoshop. Designing terrain makes much more sense with a terrain editor than trying to force your brain to see value as height. I like Terragen.

That said, you might consider just turning your dragon pic into a greyscale image for the heightmap, and then doing all the terraforming of features like hills and whatnot in-world.

If you have access to a Macintosh, my free, open-source land editor, Backhoe will do the trick. It will let you import any 256x256 graphic image (png, jpg, tiff, gif) into the height layer of a raw file. Then you can use the program to help visualize what it will look like (it displays in 3D), and then use the tools to smooth, roughen, alter the height, etc....

Excellent!
I'm off to try it right now!
Thanks!