the ideal practice is to match the image's resolution with the intended size of the division. for example, if the division is 1280x720, then the recommended image resolution is 1280x720 as well. image start to pixelate once images is scaled up or down.
if its an outdoor digital display, determine the resolution - having an image that's 16000x9000 will not help if the screen resolution is only 1920x1080
best regards
-ADMIN