Free Screen Capture
A screenshot, screen capture, or screen dump is an image taken by the computer to record the visible items displayed on the monitor or another visual output device. Usually this is a digital image taken by the host operating system or software running on the computer device, but it can also be a capture made by a camera or a device intercepting the video output of the computer.
Screenshots, screen dumps, or screen captures can be used to demonstrate a program, a particular problem a user might be having or generally when computer output needs to be shown to others or archived.
All three terms are often used interchangeably; however, some people distinguish between them as follows:
Outputting the entire screen in a common bitmap image format such as BMP, PNG, or JPEG.
The display system dumps what it is using internally upon request, such as XWD X Window Dump image data in the case of X11 or PDF in the case of Mac OS X. As of Mac OS X 10.4, pictures are no longer saved as PDF. They are saved as PNGs.
Screen capture (screencaps)
Capturing the screen over an extended period of time to form a video file. (see video capture)