diff --git a/lib/private/image.php b/lib/private/image.php
index df49bf9848d89f260ba2656b6ef3749adb6cd409..d108360b2a881c3e34c3000c345259a138654545 100644
--- a/lib/private/image.php
+++ b/lib/private/image.php
@@ -202,23 +202,23 @@ class OC_Image {
 		if($mimeType !== null) {
 			switch($mimeType) {
 				case 'image/gif':
-					$this->imageType = IMAGETYPE_GIF;
+					$imageType = IMAGETYPE_GIF;
 					break;
 				case 'image/jpeg':
 				case 'image/pjpeg':
-					$this->imageType = IMAGETYPE_JPEG;
+					$imageType = IMAGETYPE_JPEG;
 					break;
 				case 'image/png':
-					$this->imageType = IMAGETYPE_PNG;
+					$imageType = IMAGETYPE_PNG;
 					break;
 				case 'image/x-xbitmap':
-					$this->imageType = IMAGETYPE_XBM;
+					$imageType = IMAGETYPE_XBM;
 					break;
 				case 'image/bmp':
-					$this->imageType = IMAGETYPE_BMP;
+					$imageType = IMAGETYPE_BMP;
 					break;
 				default:
-					$this->imageType = IMAGETYPE_PNG;
+					$imageType = IMAGETYPE_PNG;
 					break;
 			}
 		} else {