A very lucky shot of Morty peering at the passing cars. He stayed in this position for a good minute, which allowed for this cool, candid shot. It's hard to tell, but there's a screen in front of him, which is what he's holding on too.
Haha I forgot about those posters. This picture also looks like the Garfield stuffed toys with suction cup hands every parent had on their car window in the 90's