Looked it up on Google and went back 10 pages in this subforum, but I haven't been able to find this:

How to change the image displayed by a flame (Particle flame) without owning the flame itself? Let's say I want to sell a "texture" for the flame, and I want to show the whole flame with the new "texture". Is there a file I have to change in my toribash folder?

Asking because of this request:
http://forum.toribash.com/showthread.php?t=418322

It should be flame.tga in the custom folder.

Solved, thank you Sly.