New the the forum and this is my first Post. I picked up a X940BT on Saturday from best buy, Got if for $400 out the door. It was an open box missing the USB cord. everything else was there and the unit itself was in the bag and still had the plastic on it, so it wasn't a display model. Im still waiting on my install kit and new dash bezel (going into a 99 Corvette which is only DIN and a half so it needs some modification) 

Im excited to get it installed and all set up.  Now i just have to find some instructions that tells me how to change the screen image and how big it needs to be. 

It is very easy, using Paint, you can resize any image to 800x480, save it as a jpeg, then put it on a micro SD card. On the x940 there is a menu that has a few built in pictures, but when the card is in the slot on the head unit, you will see that you can select it in the menu to change start screens.