Why are there "text formatting" options for image objects?

[Ops]

I would like to have an image object where I can change the 
backgroundcolor...for images with text, I thought I'd use the "noop" ink 
because the docs say that the backgound will be tranparent but "text 
will still show through", yet I can't seem to figure out how to PUT text 
on an image...and since "text formatting" exists for image objects, I 
have to assume there is *some way* to put text (that will "show 
through") on an image object.  Is there an image type I can use that has 
"layers" where Rev can color one layer (background) with, say white and 
another layer (text) black?  In this scenerio, I'd like to switch the 
image "background" between white and gray, still letting the black text 
"show through".