fix imagejpeg() parameter, should be NULL instead of empty string
diff --git a/system/libraries/Image_lib.php b/system/libraries/Image_lib.php
index 54a134f..6d54936 100644
--- a/system/libraries/Image_lib.php
+++ b/system/libraries/Image_lib.php
@@ -1491,7 +1491,7 @@
 		{
 			case 1	:	imagegif($resource);
 				break;
-			case 2	:	imagejpeg($resource, '', $this->quality);
+			case 2	:	imagejpeg($resource, NULL, $this->quality);
 				break;
 			case 3	:	imagepng($resource);
 				break;