lucy24 - 12:03 am on Jan 11, 2013 (gmt 0)
'the average person' has difficulty seeing the difference of images above 300 dpi.
Especially in a browser, where pixels are a unit of measure rather than a physical count, so the original resolution makes no difference.
Come to think of it, I have no idea what my monitor's physical resolution is. My first computer was 72-- black and white, of course-- back when That Other Platform prided itself on 96 and a pixel was both a unit of measure and a physical dot. Basically the same as a typesetter's point. The printer claims to go up to 600dpi.