I've just upgraded to 1.5.20 from 1.5.15. Both using the default "Curve" theme. For the earlier ver, I remember there is an option in settings whereby I can choose for the full-size image to appear on the next page or in a pop-up window when click on the thumbnail.
However, I can't find this option in 1.5.20. I might have missed this out.... Can somebody enlighten me?
http://documentation.coppermine-gallery.net/en/configuration.htm#admin_thumbnail_to_fullsize
Thanks!!