Screenshots

A screen shot, alternatively called screen dump, is a computer graphic with the contents of the screen frozen at the time of its capture recorded. Screen shots are useful for demonstrating or presenting software, or dealing with system problems.

As of the first Mac, screenshots could be produced by pressing command-shift-3. In Mac OS 7.6, command-shift-4 was added to capture only portions or active windows, as well as saving screenshots to memory instead of to file.

Keystrokes

 * Command-Shift-3: Takes a screen shot and saves it to file.
 * Control-Command-Shift-3: Takes a screen shot and saves it to memory. (Only in Mac OS 7.6 or later.)
 * Command-Shift-4: The cursor becomes a crosshair. Select a part of the screen to save that part to file. (Only in Mac OS 7.6 or later.)
 * Command-Shift-4 + Caps Lock: The cursor becomes a bullseye. Select a window to save that part to file. (Mac OS 7.6 - Mac OS 9.2.2 only.)
 * Command-Shift-4, then spacebar: The cursor becomes a crosshair, then a camera, and a window is highlighted. Select a window to save that part to file. (Mac OS X only.)
 * Control-Command-Shift-4: The cursor becomes a crosshair. Select a part of the screen to save that part to file. (Only in Mac OS 7.6 or later.)
 * Control-Command-Shift-4 + Caps Lock: The cursor becomes a bullseye. Select a window to save that part to memory. (Mac OS 7.6 - Mac OS 9.2.2 only.)
 * Control-Command-Shift-4, then spacebar: The cursor becomes a crosshair, then a camera, and a window is highlighted. Select a window to save that part to memory. (Mac OS X only.)

File Formats
Until Mac OS X, all screenshots were stored as PICT files. In earlier versions of the Macintosh system, they were also saved as MacPaint paint documents.

As of Mac OS X, the screenshot format has changed. Until Mac OS X 10.2, they were saved as TIFF files; as of Mac OS X 10.2, they were saved as PDF files.

Limitations
Early versions of the Macintosh system named the screenshots Screen 0, Screen 1 until Screen 9. If no "Screen" document was renamed, it would be impossible to continue taking screenshots. Any attempt would case the Mac to beep.

Screen shot applications

 * Grab (Mac OS X)
 * Snapz Pro (Classic Mac OS)
 * Snapz Pro X (Mac OS X)