Alright, success!!
I can now do the backgrounds, but the only trouble is that the program I have insists that you use the specific id number when you name the image you want to use. I'd prefer to use one that allows you to name it anything you like, so that everything is easier to find and use later.
Oh well, can't have everything. I'll keep looking for one, but if anyone knows of one I'd be thankful if you could let me know where it is.
Once again, Cheers for the help Gillsman! I wouldn't have got anywhere near this far if it wasn't for reading all your help on this board and elsewhere.