Remove image height/width attributes from Image Widget

It is not possible to remove it from attribute filter. When rendering image, plugin is doing as below.

$output .= rtrim("<img $hwstring");
foreach ( $attr as $name => $value ) {
  $output .= sprintf( ' %s="%s"', $name, $value );
}
$output .= ' />';

It is attaching width and height string beforehand and only applying attribute. Sad thing is that width and height is not kept in attribute filter.

**
I am not sure this should be posted as answer. I posted here because I could not comment in your question.**