grouped items on taskbar

Hey, maybe a stupid question but when I first installed windows 7 it showed large images of grouped items, now I only see text. Don't know why it changed... Already checked out the taskbar properties, but saw no option to change it back. Does somebody know how?

Sorry already fixed, for some reason when I start VLC Media player the grouped items go in text. Weird.

Thanks for the update, glad you got it fixed