You will need-
1) Computer (Desktops Only!)
Access to the rear of the computer tower
A modest understanding of your OS (To set the screen saver)
Step 1: Find Victim
Step 2: Find Image
Step 3: Set Image as Screen Saver
Click on the drop down bar, select "Pictures, select "Use Pictures and Videos From...",
Browse the folder with the LCD Screen image in it,
and click "OK".
ALSO---- Make sure the time before the screen saver turns on is set to the absolute lowest, say 30 seconds. If your PC will go into it's screen-saving state before then , make it do so!