moving and scaling an image

[David Glasgow]

Hello folks,

I am trying to get an image to slide from the middle of the screen either to the top or the bottom.  However, the screen has a perspective, as if you were looking down a bowling alley, with a vanishing point somewhere above the screen.

To maintain the sense of depth, images 'pushed away' should shrink into the distance, and ones 'pulled' closer should embiggen.  Any suggestions how this could best be achieved?

The eventual destination of this may well be iPad, so any special considerations there would be welcome.

Cheers,

David Glasgow