Override the default lightbox

Hi, great theme, though took a while to create full width pages… Is it possible to override the lightbox? as i am using “photoswipe” and i cannot get it to work, plus i cant seem to find in the css where to change the font size of the photo titles in the gallery so i have had to hide them…

http://paintersblockholidays.com/

thank you in advance
Melanie