Bug#696323: Bug fixed upstream

[Stéphane Démurget]

Note that I fixed the bug upstream :
https://bugzilla.gnome.org/show_bug.cgi?id=504729

We removed the thumbnailing and switched to mutter-like higher
resolution icons, to be able to distinct them better, as more and more
applications are providing high res icons and it makes alt-tab blazing
fast again.

Could you consider both patches for inclusion into Wheezy?
There are not very obtrusive.