Here is another possibility, it alters the image markup when you select an image to add to your content in the editor
add_filter( 'image_send_to_editor', 'remove_img_attribute', 10, 8 );
function remove_img_attribute( $html, $id, $caption, $title, $align, $url, $size, $alt )
{
$imagetpl="<figure>
<a href="https://wordpress.stackexchange.com/questions/129666/%s" title="https://wordpress.stackexchange.com/questions/129666/%s"><img src="https://wordpress.stackexchange.com/questions/129666/%s" alt="https://wordpress.stackexchange.com/questions/129666/%s" class="img-responsive %s" /></a>
%s
</figure>";
$figcaption = (!empty($caption)) ? sprintf('<figcaption>%s</figcaption>',$caption):null;
$image = wp_get_attachment_image_src($id,'large');
return sprintf($imagetpl,$image[0],$title,$image[0],$alt,$align,$figcaption);
}