Despite the advice in the article, never use an <img> tag with an empty src attribute - it causes the page itself to be requested, which is probably a larger request than just serving up a low res image in the first place.
Otherwise lots of interesting points here, and a lot of thought given to the fine details a lot of us would otherwise skip over. Good work mate
Wicky and I chatted on Twitter -- I think this is only a case for certain older browsers. Haven't seen an issue with anything like this in recent browsers in the last few years
I've done some investigation and you're right, it seems that it's been fixed in the majority of modern desktop browsers. As far as I can tell Chrome, FF, Opera, Safari and IE (9+) have resolved this issue [1][2][3][4]. Can't find any data on mobile browsers, haven't got the patience.
Otherwise lots of interesting points here, and a lot of thought given to the fine details a lot of us would otherwise skip over. Good work mate