detect progressive jpeg loaded

gistfile1.js

// check if PROGRESSIVE image was loaded
var duration = 60,
    interval = setInterval(checkImageLoaded, duration),
    maxTime  = 3000;

function checkImageLoaded(){
    maxTime -= duration;
    // image was loaded (or should have been)
    if( photo.naturalWidth ){
        clearInterval(interval);
        doStuff();
    }
    if( maxTime < 0 )
        clearInterval(interval);

playground page - http://jsfiddle.net/vsync/93jfc/1/