At 1x1 I don't expect any difference. It would be the average of all pixels in the image if you don't unevenly weight them (which you might decide when choosing

At 1x1 I don't expect any difference. It would be the average of all pixels in the image if you don't unevenly weight them (which you might decide when choosing a main color, but no downscaling algorithm would do) and the only difference is whether you remembered to gamma-correct.