diff --git a/system/libraries/Image_lib.php b/system/libraries/Image_lib.php
index 88c9e7e..8786d9d 100644
--- a/system/libraries/Image_lib.php
+++ b/system/libraries/Image_lib.php
@@ -972,7 +972,7 @@
 			$cmd_inner = 'pnmscale -xysize '.$this->width.' '.$this->height;
 		}
 
-		$cmd = $this->library_path.$cmd_in.' '.$this->full_src_path.' | '.$cmd_inner.' | '.$cmd_out.' > '.$this->dest_folder.'netpbm.tmp';
+		$cmd = $this->library_path.$cmd_in.' '.escapeshellarg($this->full_src_path).' | '.$cmd_inner.' | '.$cmd_out.' > '.$this->dest_folder.'netpbm.tmp';
 
 		$retval = 1;
 		// exec() might be disabled