A bit of jQuery I used recently for debbugging, to highlight all img-tags with missing width/height params:
$('img:not([width]),img:not([height])').css({border: '3px dashed red'})

Here's a plain js version that works without jQuery: document.styleSheets[0].insertRule('img:not([width]),img:not([height]){border: 3px dashed red}')