diff --git a/includes/mime_detect.inc b/includes/mime_detect.inc
index 0914f62b..386bbf94 100644
--- a/includes/mime_detect.inc
+++ b/includes/mime_detect.inc
@@ -148,7 +148,7 @@ class MimeDetect {
     "jp2" => "image/jp2",
     "png" => "image/png",
     "tiff" => "image/tiff",
-    "tif" => "image/tif",
+    "tif" => "image/tiff",
     "djvu" => "image/vnd.djvu",
     "djv" => "image/vnd.djvu",
     "wbmp" => "image/vnd.wap.wbmp",