A screenshot is an image taken by a user to record the visible elements displayed on a computer screen, or a monitor. Taking screenshots is made possible by the use of the operating system such as Windows or a Mac or with the help of specialized screenshot software that is running on the computer. It is estimated that the very first screenshot was created with the advent of interactive computers, which was around 1960. Eventually over time, through the 80's when computer research and development was at its peak, operating systems evolved over time.
Interestingly, the first couple of versions of various operating systems did not have the built-in functionality to capture screenshots. The next best alternative was to take a screenshot of the "text-only" screens which could be sent to a text file. This was limited because only the content of the screen was captured and not the design.
In the days of BASIC programming language, some computer systems has the "BSAVE" command that was used to capture the area of memory where the screen data was stored, but again this limited to the BASIC prompt alone.