I am trying to build a Wordpress website using a theme I purchased, unfortunately the maker of the theme doesn't seem to respond to any support requests.
After creating a few pages I noticed that performance is much worse on Safari compared to any other browser. I tested this on a few computers and few versions of macOS.
Example page is https://sochacki.info/proj/nepal-manaslu-circuit/
I realise that photos on the website are quite big (4000px each), but that is exactly what I want. I am happy with how quickly the pages load and how the galleries work, in Chrome, Firefox or Opera. When you click on a picture it loads PhotoSwipe JavaScript gallery so you can see them in full size, and then you can also click in top right corner to go full screen as well, or to leave the PhotoSwipe viewer. Switching between photos, going full screen or leaving PhotoSwipe are instant.
However when I load the same page in Safari, any action after clicking on a photo is slow. Switching between photos, going full screen, leaving full screen. It all takes a second or a few seconds. I can also see in Activity Monitor that CPU is used way more in Safari.
I tried a couple of things:
the theme I am using uses a custom plugin made by the same author to create these galleries, place photos and it includes PhotoSwipe files inside. Those files were one version behind (4.1.2 instead of latest 4.1.3) so I updated them, but the performance issues are the same.
I installed some other gallery plugins which use PhotoSwipe to display photos, and they did not have the performance issues, so I am not blaming it on PhotoSwipe, probably some other part of the plugin is causing the issues.
I have no real experience with JS or web development, are there any tools that could help me find what is causing the slow performance?
