                 res.setHeader 'Content-Disposition', disposition
                 res.setHeader 'Content-Type', 'application/zip'
 
+                # Append all photos to the archive.
                 async.eachSeries photos, addToArchive, (err) ->
                     if err
                         log.error "An error occured: #{err}"
                     else
+                        # Make the archive as ready.
                         archive.finalize()
 
 

                        log.raw err
                        cb()

                laterStream.on 'ready', (stream) ->
                    archive.append stream, {name}
                    cb()


                # Start the streaming.
                archive.pipe res

                # Abort archiving process when the user aborts his request.
                res.on 'close', ->
                    archive.abort()

