Index: image.module
===================================================================
--- image.module	(revision 6666)
+++ image.module	(working copy)
@@ -51,7 +51,7 @@
  * Implementation of hook_perm
  */
 function image_perm() {
-  return array('create images', 'view original images', 'edit own images', 'edit images');
+  return array('create images', 'view original images', 'edit own images', 'edit images', 'download images');
 }
 
 /**
@@ -408,7 +408,8 @@
  * upload.module is enabled, users will the 'view uploaded files'permission to
  * view images.
  */
-function image_file_download($filename) {
+function image_file_download($filename, $download = FALSE) {
+  $headers = array();
   $filepath = file_create_path($filename);
   $result = db_query("SELECT i.nid, f.filemime, f.filesize FROM {image} i INNER JOIN {files} f ON i.fid = f.fid WHERE f.filepath = '%s'", $filepath);
   if ($file = db_fetch_object($result)) {
@@ -422,10 +423,12 @@
         $images = (array) $node->images;
         unset($images[IMAGE_ORIGINAL]);
         if (user_access('view original images') || in_array($filepath, $images)) {
-          return array(
-            'Content-Type: '. mime_header_encode($file->filemime),
-            'Content-Length: '. (int) $file->filesize,
-          );
+          $headers[] = 'Content-Type: '. mime_header_encode($file->filemime);
+          $headers[] = 'Content-Length: '. (int) $file->filesize;
+          if ($download) {
+            $headers[] = 'Content-Disposition: attachment; filename="'.$filename.'"';
+          }
+          return $headers;
         }
       }
       return -1;
@@ -467,6 +470,13 @@
     if (!user_access('view original images')) {
       unset($links['image_size_'. IMAGE_ORIGINAL]);
     }
+    if (user_access('download images')) {
+      $links['image_download'] = array(
+        'title' => t('download'),
+        'href' => 'image/view/'.$node->nid.'/_original/download',
+        'query' => 'size='. IMAGE_ORIGINAL,
+      );
+    }
   }
 
   return $links;
@@ -798,7 +808,7 @@
  * image/view/$nid/$label
  * (e.g. image/view/25/thumbnail or image/view/14)
  */
-function image_fetch($nid = 0, $size = IMAGE_PREVIEW) {
+function image_fetch($nid = 0, $size = IMAGE_PREVIEW, $download = FALSE) {
   if ($size == IMAGE_ORIGINAL && !user_access('view original images')) {
     return drupal_access_denied();
   }
@@ -812,7 +822,7 @@
 
       if (isset($node->images[$size])) {
         $file = $node->images[$size];
-        $headers = image_file_download($file);
+        $headers = image_file_download($file, $download);
         file_transfer($file, $headers);
       }
     }