Is there any way to make the thumbnails larger in Vista?

[ScotteusMaximus]

i'm talking about the thumbnails that come up when you hover over things on your taskbar. right now they're too small to be of any real use outside of nifty eye candy.

edit: how do you make thumbnails larger in folders with pictures in them? i remember seeing screenshots with a slider at the bottom where you can resize the thumbnails as big or small as you want. i can't seem to find that option either...