Check what attached image size is used

I think I’d use the get_image_tag filter for this – it provides you with the size as one of the parameters. Something along the lines of:

function wrap_wide_image_tags($html, $id, $alt, $title, $align, $size) {
    if($size == 'wide-image') {
        $html="<div class="wrap-wide-image">".$html.'</div>';
    }
    return $html;
}
add_filter('get_image_tag', 'wrap_wide_image_tags', 10, 6);

Hope this helps!