add a column to the users table to hold the image name.
Security Assist will create a page to update the user record, add a file field to the form on that page. add the upload file behavior, this will create a new binding group on the bindings panel named WA UPlaoded Files (<file field name>), this binding group will have a binding for Server File Name
You then need to edit the Update record server behavior that is on that page, and bind the image column to the Server file name binding.