OK this bug is OLD and still not fixed so after a long time I finally decided to post it here cause it's severely debilitating.
Basically Instagram embedded images on various websites do not work. For example, here is a local news website which often embeds Instagram images and I cannot view them with Maxthon 188.8.131.520: http://www.24ur.com/ekskluziv/tuja-scena/elizabeth-hurley-se-sonci-zgoraj-brez.html
Other web browsers (Internet Explorer, Firefox, Chrome) work fine. Switching modes (Webkit / Trident) does not make a difference.