Filter the gform_heading div?

I figured how to make this work for us. I'm using the "gform_pre_render" filter and appending our custom content to $form["description"]

If anyone else is interested, here's a quick sample of the complete code:

add_filter("gform_pre_render", "add_custom_content");

function add_custom_content($form){
	$form["description"] .= '<img src="custom-image.png" alt="An image that will be inserted in the description of all forms." />';
  return $form;
}