How to take a screenshot in Red Hat Linux

Desktop Image: Use the 'Prt Scr' key. This will take a snapshot of the desktop by launching the utility gnome-panel-screenshot or ksnapshot and request where to save the resulting PNG image. if that fails (and it sometimes does) then try the command /usr/bin/gnome-panel-screenshot or ksnapshot.

Delayed Desktop Image:

Use the gnome-panel-screenshot
$ sleep 3; gnome-panel-screenshot
Use ksnapshot
$ ksnapshot
Use ImageMagick
$ sleep 3; import -window root ~/Screenshot.png
This command sleeps for 3 seconds before taking the snapshot image of the desktop.
Window Image: Alt + "Prt Scr" Generates image file of active window.