Screenshot tools in ubuntu
Press the PrtSc or (Print Scrn, Prt Scn, Prt Scr, Prt Scrn) to capture the entire desktop
Press Alt + PrtSc to capture the currently active window.
Go to Applications->Accessories->Take Screenshot
Go to Applications->Accessories->Terminal
Type the below command and hit enter.
Click and select the area to take the screenshot. Change screenshot.jpg to any file name or any other extension ex ( .png).Open your home directory to see the screenshot file.