Shortcuts in the Picasa Photo Viewer Ctrl-U: Single image upload Ctrl-R: Rotate the image clockwise Ctrl-Shift-R: Rotate the image counter-clockwise Ctrl-8: Add a star Left and right arrow keys: Scroll through images Mousewheel: You can zoom and scroll through photos. Alter the way the mousewheel behavies by clicking the down arrow menu > Configuration. You can choose between two options:    Zoom with mousewheel (hold Ctrl to navigate)    Move…