kristarella on "wp_get_attachment_image_attributes filter not working"

I've seen this filter in a few places on the net and I've looked at the core WP code, as far as I can see this should work, but it doesn't work at all.

function remove_img_title($atts) {
	unset($atts['title']);
	return $atts;
}
add_filter('wp_get_attachment_image_attributes','remove_img_title',1,1);

Obviously I'm trying to remove the title attribute from images inserted to posts... I've also tried replacing the title with an arbitrary string, but that doesn't work either. I saw in another forum Q that their filter was only working for posts with feature images, so I tried featuring the image... still doesn't work.

Please help!