Hi all, I know there are some tutorials on scrolling backgrounds but in the end I decided to use the way that I did when I was using App inventor.
I use 2 images both same size as my screen size. eg 480,850
Set image 1 position at 0,0
Set image 2 position at -850
Add bullet to each and set angle of motion and speed the same for each.
For example. Vertical scroll angle of motion 90
Speed 100.
On start of layout set it all going and when each image reaches y >= 850 return it back to Y-849. Yes 849! this stops any gaps between the images!
Hope this helps!