09-22-2021, 11:36 PM
It's inches-at-resolution. Not just inches.
So, if the image is 10x10 inches at 72 dpi then when displayed at 72dpi you will see it at 10x10 inches.
If your display is 3840 by 2160 pixels scaled to 2560 x 1440 (Late 2013 27-inch Retina iMac defaults) then you're viewing at an approximate 109dpi.
At this scale, you're seeing your 72dpi image scaled down to roughly 66% of the size that it would have on a 72dpi display. Your 10-inch image is now displaying at only 6.6 inches.
So, if the image is 10x10 inches at 72 dpi then when displayed at 72dpi you will see it at 10x10 inches.
If your display is 3840 by 2160 pixels scaled to 2560 x 1440 (Late 2013 27-inch Retina iMac defaults) then you're viewing at an approximate 109dpi.
At this scale, you're seeing your 72dpi image scaled down to roughly 66% of the size that it would have on a 72dpi display. Your 10-inch image is now displaying at only 6.6 inches.