Wordpress remove content image dimensions without regexp

functions.php

function remove_img_dimensions($html) {
		$dom = new DOMDocument;
		$dom->loadHTML($html);
		$imgs = $dom->getElementsByTagName('img');

		foreach ($imgs as $img) {
			$img->removeAttribute('width');
			$img->removeAttribute('height');
		}

		$html = $dom->saveHTML();

	    return $html;
	}

add_filter('the_content', 'remove_img_dimensions');