[Linux] How do I make images appear in offline documentation?

I installed Matlab 2018b on Ubuntu 18.10.

When I search for a function in the help box (top-right by default), I do get to the page for that function.

However, the images for examples for the funciton do not appear. I instead get a small red square in place of the image.

The same issue also exists on Solus (another Linux distro).