I have customized my alt-tab screen with the following:
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\AltTab] "OverlayIconPx"=dword:00000040 "MaxThumbSizePx"=dword:00000100 "MinThumbSizePcent"=dword:00000064
It works great: the thumbnail becomes 256 pixel wide and the icon at the corner of the thumbnail becomes 64x64 pixels. However, Windows doesn't load the high-res icons from the programs; instead, it uses the 16x16 pixel icon and scaled it up by nearest-neighbor. I'm sure the programs has high-res icons because I saw them with in "Extra Large Icon" view in Explorer.
So the question is: How can I force Windows to load the high-res icons for the alt-tab thumbnail preview? (Perhaps a registry key, or a .dll hack/injection?)