I am trying to find the native/best resolution for both backgrounds and the splash screen for my Avic Z2, which has been flashed to a Z3 firmware. While I am getting the aspect ratio correct, I find that they look grainy once I put them on my unit. If someone could let me know, I would be most grateful. I looked in the manual, and it only gave me the maximum resolution for an image, which is a little misleading, as the Avic just downsamples it to make it fit on the screen.

 

Any input would be appreciated, thanks!