I need your help again:

The default rotation origin of the image frame is the lower left corner. How can I change this?
I want to rotate the center of the background image around MoIs 0,0,0 coordinate.

I found this in the Javascript documentation but it has no effect:
img.frame.newOriginX = img.width/2;
img.frame.newOriginY = img.height/2;

-Martin