Here is the Complete Collection of gowns. Download size is 2560x1440, so it should be resizeable to fit most desktop sizes if you want to use it as a wallpaper.
The series:Thor and CapIron Man and HulkBlack Widow and HawkeyeCoulson, Fury, and HillLoki
and if you're interested, here you can find all the backviews
of the gowns (they're quite sketchy).
Also, I've been honored by quite a few cosplayers making these gowns or gowns based on these themselves! You can find my growing list here.