This is a slight rework of a post I made on an old blog back in 2011, with a bit of an update to elaborate on a couple of points.
Originally this was in response to an article written by a particularly well known photographer claiming to “bust” some myths that his article actually end up reinforcing and propagating (which might explain why his post now seems to have magically vanished from the web).
I’d had a little back and forth on Twitter with this person regarding his new article and why PPI doesn’t matter when resizing images for digital display (meaning, on the screen, on the web, via digital projector running off a laptop, via a mobile device, whatever) which he claimed was a myth, and that it does matter.