You do not need an Artstor account to download (save) a .jpg image from the Artstor database.
However, you will need an Artstor account to set up your own folder within Artstor, to use the Offline Image Viewer (OIV), or to access folders that someone else (i.e. your instructor) might have set up for you to use.
This is not connected to your other Camosun accounts.