Images have suddenly dissapeared from site

https://www.geoinvestigate.co.uk/

This is the site I built at the start of summer of this year.
I was doing a maintence check of all the sites I build today and for some reason the logo (top left) and the case study images (which can also be found on a slider in the footer) have dissapeared for some un-known reason. I’ve tried deleting, then re-selecting the files in the theme option panel but they still aren’t appearing. Any ideas to why this is happening? I tried installing the latest version of wordpress but still having no luck!

The theme i’m using is: Nimble by Dream Team

Not sure if it’s a wordpress error or an error with the theme.

Thanks
Emma