diff --git a/htdocs/lib/files.lib.php b/htdocs/lib/files.lib.php
index 603d85b23c4..34f1b751858 100644
--- a/htdocs/lib/files.lib.php
+++ b/htdocs/lib/files.lib.php
@@ -225,7 +225,7 @@ function dol_mimetype($file,$default='application/octet-stream',$mode=0)
 	if (preg_match('/\.png$/i',$tmpfile))					   { $mime='image/png'; $imgmime='image.png'; }
 	if (preg_match('/\.gif$/i',$tmpfile))					   { $mime='image/gif'; $imgmime='image.png'; }
 	if (preg_match('/\.bmp$/i',$tmpfile))					   { $mime='image/bmp'; $imgmime='image.png'; }
-	if (preg_match('/\.tiff$/i',$tmpfile))					   { $mime='image/tiff'; $imgmime='image.png'; }
+	if (preg_match('/\.(tif|tiff)$/i',$tmpfile))			   { $mime='image/tiff'; $imgmime='image.png'; }
 	// Calendar
 	if (preg_match('/\.vcs$/i',$tmpfile))					   { $mime='text/calendar'; $imgmime='other.png'; }
 	if (preg_match('/\.ics$/i',$tmpfile))					   { $mime='text/calendar'; $imgmime='other.png'; }