Choosing the best size and pixel picture:
Ideally you should have 60 pixels high if you are going to display pictures or video. This means if you only have 2′ of height available, you would want an 8mm rather than a 10mm LED. If you are going with a 4′ x 8′ sign you may be able to use a 16mm as long as the viewing distance is greater than 100′.