Theme restaurateur – images in slider are suddenly 1 px big

On https://www.biobrunch.nl I had a on the homepage a built in and working slider with several images 965 x 450 px big. It was working great.

A few days back I discovered that my slider is still working, but now only the background color of the images are showing and when I look at the pictures-element is says just 1px.

Can anybody tell me what is wrong.

I deleted the images from the slider and also out of the media library. Then uploaded everything again. Still the same problem.