Interesting article on web and mobile performance with regard to rendering and display of JPEG images.
Progressive JPEG FAQ:
The article also gives ways to identify a progressive JPEG and a way to convert baseline JPEGs to progressive JPEGs.
And the comments, both on the original article, and in this HN thread about it ( http://news.ycombinator.com/item?id=4983073 ), are informative too.
Google mod_pagespeed, which I blogged about recently, has support for progressive JPEGs.
- Vasudev Ram