I solved my problem by not doing i.
Instead of one big background image for all the screen I broke the background into two parts, a top and bottom, leaving the center of the screen clear.
Now I can place my small images there and they appear just fine.
I see a lot of screens designed with single background images, so it must be possible, but isit just alimit that you cant put images on the image. Buttons, LEDs etc seem OK, images dont work.
Anyway, I have a work-around.
thanks