(developed by Aescripts) is a plugin designed specifically to give you that control. It goes beyond simple "mosaic" effects, offering precise algorithmic dithering techniques used in old-school printing and early computing.
PixDither: When After Effects Learns to Speak in Pixels pixdither plugin after effects
Lower the "Scale" or "Resolution" slider until you achieve the desired pixel size. (developed by Aescripts) is a plugin designed specifically