problem of slider stopped working still unresolved

hi there,
until today the flex sliders of my gallery posts worked flawlessly. then i updated the fukasawa theme and suddenly the images of each gallery post are shown vertically ordered and the slider is gone. i changed back to the previous version of fukasawa but the problem persists.
i have read through all of the forum posts concerning similar problems and it looks as if i have to re-upload all images i use in my gallery posts in order to make the flex slider work again. this is not an acceptable solution for a website with many images and i hope there is someone out there (maybe the theme developer him-/herself?) who can point out a way to solve this problem.

thank you in advance!
pigsound

The page I need help with: [log in to see the link]