Finder bugs - No jpg/pdf preview in iconview, flickering copy + icon

I updated to Snow Leopard last weekend, most things seem ok but i've got some real problems with finder.

As described in the subject.

The icon view completely fails to show me some jpegs or pdf contents, it just stays as a jpeg or pdf icon from preview. Quite frustrating when the zooming and multipage pdf navigation is one of the features meant to be in Snow Leopard.

Other than that whenever i try to copy a file or folder the green + in a circle that goes next to the icon i'm dragging with the mouse flickers like crazy.

I've rebooted, no joy. Anyone else suffer this or have any tips?