for @Jonidag and everyone else who come across this issue:
I wrote a tutorial about how to fully optimize the Minimal theme gallery. It teaches you how to add a slideshow to the product page which includes swiping feature, arrows, lazyload (makes the page loads faster), and much more - actually 20+ customizable features are included.
You can click here to read the tutorial and download the code. I'll be happy to answer any questions!