My Epson r280 has max resolution of 5760 x 1440. Can anyone tell me what resoluton to send to printer for best quality. When I have prints done at Mpix, I send them at 240 ppi. I want to think that 240 or 360 divides into above numbers evenly and they would be best. Am I all wet? Any help would be greatly appreciated. I have not done my own printing of images in the past.