Index: imagefield_file.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/imagefield/imagefield_file.inc,v
retrieving revision 1.2
diff -u -r1.2 imagefield_file.inc
--- imagefield_file.inc	30 Jul 2008 17:49:35 -0000	1.2
+++ imagefield_file.inc	6 Aug 2008 17:34:16 -0000
@@ -21,8 +21,15 @@
 
 function imagefield_file_insert($file) {
   // create and admin thumbnail.
-  if (imagefield_file_is_image($file)) 
-    image_scale($file->filepath, imagefield_file_admin_thumb_path($file), 100, 100);
+  if (imagefield_file_is_image($file)) {
+    $info = image_get_info($file->filepath);
+    if($info['width'] < 100 || $info['height'] < 100) {
+      image_resize($file->filepath, imagefield_file_admin_thumb_path($file), $info['width'], $info['height']);
+    }
+    else {
+      image_scale($file->filepath, imagefield_file_admin_thumb_path($file), 100, 100);
+    }
+  }
 }
 
 function imagefield_file_delete($file) {