Responsive Single Item

I have got the plugin working with singleItem=true with the following:

[owl-carousel category="Front Page" singleItem=true autoPlay=true]

The single item demo on the Owl website resizes to fit the window size https://www.owlgraphic.com/owlcarousel/demos/one.html

However, this does not happen with the plugin and the pictures remain at their full size regardless of the size of the window.

This happens with autoPlay=true and false.

https://www.ads-software.com/plugins/owl-carousel/