diff --git a/filesystem/File.php b/filesystem/File.php
index ca0b51c9e..8f5124220 100644
--- a/filesystem/File.php
+++ b/filesystem/File.php
@@ -808,7 +808,7 @@ class File extends DataObject {
 			'htm' => _t('File.HtmlType', 'HTML file')
 		);
 		
-		$ext = $this->getExtension();
+		$ext = strtolower($this->getExtension());
 		
 		return isset($types[$ext]) ? $types[$ext] : 'unknown';
 	}
diff --git a/tests/filesystem/FileTest.php b/tests/filesystem/FileTest.php
index 1466810a8..750479ad5 100644
--- a/tests/filesystem/FileTest.php
+++ b/tests/filesystem/FileTest.php
@@ -249,6 +249,9 @@ class FileTest extends SapphireTest {
 	
 		$file = $this->objFromFixture('File', 'pdf');
 		$this->assertEquals("Adobe Acrobat PDF file", $file->FileType);
+
+		$file = $this->objFromFixture('File', 'gifupper');
+		$this->assertEquals("GIF image - good for diagrams", $file->FileType);
 	
 		/* Only a few file types are given special descriptions; the rest are unknown */
 		$file = $this->objFromFixture('File', 'asdf');
diff --git a/tests/filesystem/FileTest.yml b/tests/filesystem/FileTest.yml
index 636339f15..47e5190aa 100644
--- a/tests/filesystem/FileTest.yml
+++ b/tests/filesystem/FileTest.yml
@@ -13,6 +13,8 @@ File:
     Filename: assets/FileTest.txt
   gif:
     Filename: assets/FileTest.gif
+  gifupper:
+    Filename: assets/FileTest.GIF
   pdf:
     Filename: assets/FileTest.pdf
   setfromname: