How to make a simple screenshot under Linux in X

To select an X window or an area of the screen with the mouse and save it in the JPEG image format to a file entitled window.jpg, use:

   import window.jpg

To capture the entire X server screen in the JPEG image format in a file entitled root.jpg, without using the mouse, use:

   import-window root root.jpg

To capture the 512x256 area at the upper right corner of the X server screen in the PNG image format in a well-compressed file entitled corner.png, without using the mouse, use:

   import-window root-crop 512x256-0+0 -quality 90 corner.png