BRILLIANT! Simple, intuitive and classy. Open, create groups, drop and drag tabs between groups, then choose any one from the icon on top at any time.
I figured it out in 10 seconds, made 3 groups in 15 more, filled them in 20, and now just have to click their icon up top, and choose one of the three groups (which you can name, and which have a little color on each one).
This is a case of programming perfection: it could not have been made better!
Change colors and change icons or add your own in several common formats - download anything. Nifty!
I even grabbed a 1200x1200 pixel jpg off my PC and it worked, and shrunk it perfectly. Most websites choke on 128x128. Dude! :)