Does :before not work on img elements?

Unfortunately, most browsers do not support using :after or :before on img tags.

http://lildude.co.uk/after-css-property-for-img-tag

However, it IS possible for you to accomplish what you need with JavaScript/jQuery. Check out this fiddle:

http://jsfiddle.net/xixonia/ahnGT/

$(function() {

    $('.target').after('<img src="https://stackoverflow.com/questions/5843035/..." />');

});

Edit:

For the reason why this isn’t supported, check out coreyward’s answer.