For a 4" x 6" print, the picture determination ought to be 640 x 480 pixels least. For a 5" x 7" print, the picture determination ought to be 1024 x 768 pixels least. For a 8" x 10" print, the picture determination ought to be 1536 x 1024 pixels least. For a 16" x 20" print, the picture determination ought to be 1600 x 1200 pixels least.