Photoria theme – pictures not showing

Hi,

I’m creating a site with the Photoria theme. I’ve made posts with featured images to have them all show in the slideshow at the top of the page as well as on the thumbnails. Everything works fine in the sense that it’s all there – except the fact that the pictures are not showing!
I’ve tried changing the troubleshooting guide:

https://www.wpzoom.com/tutorial/troubleshooting-image-display-issues/

I’ve also tried this:
In your styles.css:

.container {
overflow: hidden;
position: relative;
height: 430px !important;
}

OR

#featPostsBig div.cover {
height: 430px !important;
}

But nothing is working.
I just updated my wordpress – could it be that the theme isn’t working with the newest edition of wordpress?

Thank you.