Can't apply basic motion to JPEGs

Hi,

Can anyone help please... I've imported some JPEGs (16:9) from my Panasonic Lumix into FCP v6.0.6. When I try to apply a basic motion - eg a zoom in, using the Scale parameters - it doesn't work. Either nothing happens, or else the next shot (also a JPEG) is zoomed in, though not in accordance with the parameters I've set. It works fine when I'm applying the motion to a normal HDV clip. What's going on? Is there any reason I can't apply a basic motion to my stills in the same way as to a video clip?

Thanks in advance