Helper::get_thumbnail_url( string $size = 'small' )

	public static function get_thumbnail_url( $size = 'small' ){
		$video = self::current_video_post();
		if( !$video ){
			return;
		}

		$result = false;

		$sizes = array_merge(
			/**
			 * Filter default sizes to allow additional sizes to be added.
			 *
			 * @since 2.0.15
			 *
			 * @param array         $sizes  Registered thumbnail sizes stored as size_name => thumbnail ID in video thumbnails array.
			 * @param Video_Post    $video  The current video post being processed in loop.
			 */
			(array) apply_filters( 'vimeotheque\themes\thumbnail_image_sizes', [], $video ),
			[
				'small'     => 0, // 100x75 px
				'medium'    => 1, // 200x150 px
				'large'     => 2, // 295x166 px
				'original'  => 3, // original image size ratio
				'hd_small'  => 4, // 640x360 px
				'hd_medium' => 5, // 1280x720 px
				'hd_big'    => 6  // 1920x1080 px
			]
		);

		if( !array_key_exists( $size, $sizes ) ){
			$size = 'small';
		}

		$thumbnails = array_values( $video->thumbnails );

		if( isset( $thumbnails[ $sizes[ $size ] ] ) ){
			$result = $thumbnails[ $sizes[ $size ] ];
			if( is_ssl() ){
				$result = str_replace( 'http://' , 'https://', $thumbnails[ $sizes[ $size ] ] );
			}
		}

		if( 'original' === $size ){
			$result = remove_query_arg( 'r', $result );
		}

		return $result;
	}