http://kcavallari.com/photos/displayimage.php?album=410&pid=15916#top_display_media (example)
I added a plugin which made the fullsize out of the croped one from the standard version. But why can't I copy or save the photo to my computer from either normal_ or fullsized version? It's important to me that photos at my site are open for everybody to browse, copy and save.
Thanks in advance.
Because you enabled the "anti image theft" option.
http://documentation.coppermine-gallery.net/en/configuration.htm#admin_image_transparent_overlay_start