Please note that official support for this menu version has now ceased. There are still plenty of users, though, and the forum is still running. Some of our long-time users may be able to help you out.
Now the question:
I´m using the Frames based menu, and I want to set a background image. Is that possible?
Till now, i couldn´t find this feature in the script.
You're English is fine. I'm sure there is a way to do it in frames. But, I have a couple of test pages up with the only way I could figure to do it. The info on v3 is not available anymore. I don't know if this will help you or not. Anyway, here are two pages to look at and if save the pages and the files and check them you can see how I did it. I have NO idea if that is the way to do it, but it works for me, so I use it. I make the background images and play with size until I get it right.
LINK REMOVED: In this one the image is set once for each menu.
LINK REMOVED: In this one I used the #backimage code for the horizontal menu.
The button for the top horizontal menu is 100px wide by 45px high and the one for the little button is 44 px wide by 20 px high. Hope this helps