ok, this is a pity...
i implemented the hash:false (
like here) but i just removes the parts after the #
/anywebsitewithgallery?os_image_id-45
/anywebsitewithgallery?os_image_id-46
/anywebsitewithgallery?os_image_id-47
still no working back button....
so i started to insert another lightbox. was okay but finally i switched to another gallery-extension.
i really hope you can do a workaround or fix this with a new version of fancybox. in this state it is really not comfortable and userfriendly...