wp_get_attachment_thumb_url example

function get_attachment_icon_src( $id = 0, $fullsize = false ) {
    _deprecated_function( __FUNCTION__, '2.5.0', 'wp_get_attachment_image_src()' );
    $id = (int) $id;
    if ( !$post = get_post($id) )
        return false;

    $file = get_attached_file( $post->ID );

    if ( !$fullsize && $src = wp_get_attachment_thumb_url( $post->ID ) ) {
        // We have a thumbnail desired, specified and existing.
        $src_file = wp_basename($src);
    } elseif ( wp_attachment_is_image( $post->ID ) ) {
        // We have an image without a thumbnail.
        $src = wp_get_attachment_url( $post->ID );
        $src_file = & $file;
    } elseif ( $src = wp_mime_type_icon( $post->ID ) ) {
        // No thumb, no image. We'll look for a mime-related icon instead.