I imported the code from https://github.com/nolimits4web/Swiper/blob/master/demos/23-thumbs-gallery.html
But the first problem I had was that the slider didn't show so I fixed that with adding min-height: 250px; to the div class .swiper-slide(this is the only thing I changed), my new problem is that the slider doesn't work.
When I resize the browser the slider suddenly works, I can't find what is causing the problem.
You can watch the slider at nielsvt.remvoo.com and then section portfolio, the slider will be visible at the bottom of the page
