DisplayFusion 3.5 Beta 8 doesn't resize the preview of each window like Windows 7 does it nicely ( for example with Skype ). I think it requires a specific ratio between width and height that Windows re-sizes the preview, but I might be wrong
I've uploaded a screenshot of each taskbar including a preview of Spotify + Skype. The Skype preview has been re-sized on the native taskbar.
You can also notice a slight difference between both bottom-margins. Windows 7 has a margin ( maybe of 10px ? ), DisplayFusion hasn't.
Edit:
Oh, please don't be confused because I've cut the Skype-preview from another screenshot and pasted it in on both screenshots. It might not be very well aligned but I hope it's still good enough to demonstrate the slight difference.