To be honest, I'm not sure if I really want this because I can't imagine how exactly it would look. But maybe someone is interested in this, too, or even has already written code to achieve this: it might be practical or interesting to have small thumbnail previews of a figure in the list of figures next to the caption.
This has already been briefly discussed here List of figures: source below image caption? but without any result so if anybody wants to give it a shot or has already done so: yay! :)
See Heiko's answer for an example image of how this might look.