Use the "Grab" application that Mac OS X installs. Despite its name it's not in the "Grab Bag" folder. It's in the "Utilities" folder.
As I recall the app has three modes,
* Window
* Screen
* Timed
When one of these options is selected a dialog box appears telling you what to do to take the picture.
My preference is to use the 10 second timed option that allows me to push the grab application to the background, select the right application and window, and then just wait a moment for the "flash".
Once taken, the picture appears in a window to be saved. I think TIFF is the default format.
William
