diff --git a/modules/file/file.module b/modules/file/file.module
index 7fc2980..3a2beed 100644
--- a/modules/file/file.module
+++ b/modules/file/file.module
@@ -92,7 +92,7 @@ function file_theme() {
       'variables' => array('file' => NULL, 'icon_directory' => NULL),
     ),
     'file_icon' => array(
-      'variables' => array('file' => NULL, 'icon_directory' => NULL),
+      'variables' => array('file' => NULL, 'icon_directory' => NULL, 'alt' => ''),
     ),
     'file_managed_file' => array(
       'render element' => 'element',
@@ -754,10 +754,12 @@ function theme_file_link($variables) {
     'application/octet-stream' => t('Binary Data'),
   );
 
+  $mimetype = file_get_mimetype($file->filename);
+
   $icon = theme('file_icon', array(
     'file' => $file,
     'icon_directory' => $icon_directory,
-    'alt' => (!empty($mime_name[file_get_mimetype($file->filename)])) ? $mime_name[file_get_mimetype($file->filename)] : t('File'),
+    'alt' => !empty($mime_name[$mimetype]) ? $mime_name[$mimetype] : t('File'),
   ));
 
   // Set options as per anchor format described at
@@ -788,6 +790,8 @@ function theme_file_link($variables) {
  *   - file: A file object for which to make an icon.
  *   - icon_directory: (optional) A path to a directory of icons to be used for
  *     files. Defaults to the value of the "file_icon_directory" variable.
+ *   - alt: (optional) The alternative text to represent the icon in text-based
+ *     browsers. Defaults to an empty string.
  *
  * @ingroup themeable
  */
@@ -798,7 +802,7 @@ function theme_file_icon($variables) {
 
   $mime = check_plain($file->filemime);
   $icon_url = file_icon_url($file, $icon_directory);
-  return '<img class="file-icon" alt="' . $alt . '" title="' . $mime . '" src="' . $icon_url . '" />';
+  return '<img class="file-icon" alt="' . check_plain($alt) . '" title="' . $mime . '" src="' . $icon_url . '" />';
 }
 
 /**