Normally I both record and write down my image stream. The recording part is the most important part of the image stream process if you don't have a listener. The recorder forces you to talk out loud and that is very important to successful image streams. If you don't say them out loud they tend to be unclear, easily forgotten and even too short to provide an answer. The more you describe your image stream out loud the more you are providing yourself with information of what the image stream is about. Also the recorder is useful for checking the information of a long image stream. It's easy to overlook some important details after doing the image stream.
Alex