public void DeleteFile(AttachmentBE attachment, SizeType size) {
     if (!attachment.IsHeadRevision()) {
         throw new DreamInternalErrorException(DekiResources.CAN_ONLY_DELETE_HEAD_REVISION);
     }
     for (int i = 1; i <= attachment.Content.Revision; i++) {
         string filename = FilePath(attachment, size);
         try {
             File.Delete(filename);                    
         } catch { }
     }
 }