Custom loading images

[mrpalaces]

I'm just starting with the mapping, and until now I'm having no major problems, just gainning experience with doing more and more complex forms with the brushes and texturing them. But there is something that I want to do once I've build an good enough map to publish, anf that's give it a custom loading image where I can put it's own Briefing image to explain the map's objetives. Also, in order to finish that map, I'll like to give it some custom textures that Radiant doesn't have. In the tutorial section there is a custom texturing tutorial but it says "coming soon" and I'm quite impatient. Anyway I suposse that the process to adding a custom image for the textures in the game will have some differences with the images to add to the loading screen.

I'll appreciate any help you people can give me.