Editing Features
Picasa 2 lets you fix up common problems and create great effects in your photos. There are three editing tabs filled with tools to help you improve your pictures.
Edit Tabs
Basic Fixes: One-clicks to crop, rotate, remove redeye, and more.
Tuning: Advanced features to fix contrast, and remove color cast.
Effects: Turn a grey sky blue, brighten colors, and add photographic filters.
Undo / Redo
Picasa never saves over your original files, so you'll never ruin or damage a picture by editing it. Picasa preserves your original photo as a digital negative, so every edit you make is fully undoable. If you want to work with your edited pictures in other programs, you should export or save a copy of them.
Saving Pictures
To save a version of your edited picture, choose File>Save a Copy, or use Picasa's Export to Folder tool.
Pan / Zoom
To zoom into a picture, drag the zoom slider to the right, or hold the up arrow key. When you are zoomed in, the Zoom window will appear. To pan around inside the picture, click and drag inside the Zoom window.
To zoom out, click the Fit button or hit Escape to exit. Click the 1:1 button to view a picture at its actual resolution onscreen.
Rotate
To rotate a single picture, click on the picture you want to rotate, and click the Rotate arrow. To rotate multiple pictures, shift+click or control+click to select multiple pictures, and click the Rotate arrow. If your digital camera supports auto rotate, Picasa will automatically orient your pictures correctly.
You can use ctrl+R to rotate clockwise or ctrl+shift+R to rotate counterclockwise.
Histogram & Camera Information
A real-time histogram that displays advanced EXIF information and RGB color values and intensity.
Click the propeller-beanie icon to view. (For the hard-core photographers.)