HELP - How to modify or create my own paintings?

[MADsushi]

I'm making a custom story with my friend and i want to know if anybody have a "Custom Painting" like the one that i found in this forum but in other sizes.. or may be you can say me how to simply modify one that already exist because i have seen the large paintings from the games but the texture placing use ".dds" with more than one "painting" images... and i have been having problems copying that paintings and modifying the files and textures.

This is the one that i found -> http://img823.imageshack.us/img823/2529/...ngbase.jpg

PD.: I know how to modify .DDS and create the .MAT but my problem is with the .DAE and .ENT... however if someone can give me a modifiable of a large painting I will be very grateful and if you want I can give credit when we release the Custom Story.

Sorry for my english, greetings from Chile!