Prevent division by zero error

Author: Marco Pereirinha

php/class-delivery.php

@@ -1305,7 +1305,7 @@ public function parse_element( $element ) {
 
 			// Check if this is a crop or a scale.
 			$has_size = $this->media->get_size_from_url( $this->sanitize_url( $raw_url ) );
-			if ( ! empty( $has_size ) ) {
+			if ( ! empty( $has_size ) && ! empty( $item['height'] ) ) {
 				$file_ratio     = round( $has_size[0] / $has_size[1], 2 );
 				$original_ratio = round( $item['width'] / $item['height'], 2 );
 				if ( $file_ratio !== $original_ratio ) {