Depends on your projector. My Mits HC3, HD1000, and Epson 400 all support user startup screens. Generally, you capture the user startup image from the current input.
Originally Posted by Sheridan1952 /forum/post/16891074
The procedure is detailed in the user manual. Generally though, as jrwhite said, the projector is displaying the image you want and you go into the menu to tell it to capture that image and store it.
You didn't say what projector you have, so we can't be more specific. But that capability HAS to built into the projector.