On old version of CPG (1.4.25) I have albums viewed public for all users. When upgraded to version 1.5.6 users need to register for viewing albums/photos, but this is not defined permission on settings. In shortly I liike to be albums viewed without registration. LINK (http://www.drustvo-go-para.si/galerija)
http://documentation.coppermine-gallery.net/en/configuration.htm#admin_allow_unlogged_access