UPD: sorry, this is a wrong answer, see comments. This is a correct answer.

Something like this:

images = document.getElementsByTagName('img');

for (i = 0; i < images.length; i++) {

    images[i].parentNode.removeChild(images[i]);

}

OR a slight modification of my first attempt to answer this question:

var images = document.getElementsByTagName('img');

var l = images.length;

for (var i = 0; i < l; i++) {

    images[0].parentNode.removeChild(images[0]);

}