When you create an image field, you will need to choose whether the uploaded images will be stored in the public or private file directory defined in your settings.php file and shown on the <a href=":file-system">File system page</a>. This choice cannot be changed later. You can also configure your field to store files in a subdirectory of the public or private directory; this setting can be changed later and can be different for each entity sub-type using the field. For more information on file storage, see the <a href=":system-help">System module help page</a>.