Optimize page load speed

[wschella]

There are some suggestions made by https://developers.google.com/speed/pagespeed/insights/?url=https%3A%2F%2Fzeus.ugent.be&tab=desktop

[Robbe7730]

We are currently at 100, so I guess this is fixed ;)

[wschella]

There definitely some improvements we can still make according to that page, mostly related to images.

[werthen]

I think tis issue should be offloaded to ZeusWPI, maybe imagemagick could be applied to every image uploaded there so it's all webp