/**
* Extracts the image size and WebP type from a file based on the chunk list
* @param array $chunks Chunks as extracted by RiffExtractor
+ * @param string $filename
* @return array Header data array with entries 'compression', 'width' and 'height', where
* 'compression' can be 'lossy', 'lossless', 'animated' or 'unknown'
*/
/**
* Must use "im" for XCF
*
+ * @param string $dstPath
+ * @param bool $checkDstPath
* @return string
*/
protected function getScalerType( $dstPath, $checkDstPath = true ) {