How to change image/iwi in existing maps?

[agribilos]

Hi there.
I know you can quickly edit existing images (iwi) that are used by a map to display custom images or textures. I want to know if there is an easy way to add new iwi files (so you don't have to edit the original) to be used in an existing map. Or to you have to make an xmodel and spawn using this function? Any help welcome.

		spawnModel( model, origin, angles )
{
    if( !isdefined(model) || !isdefined(origin) )
        return undefined;

    if( !isdefined(angles) )
        angles = (0,0,0);

    spawn = spawn ("script_model",(0,0,0));
    spawn.origin = origin;
    spawn setmodel (model);
    spawn.angles = angles;

    return spawn;
}