The new images are quite big - the first load for me is visibly slow, especially hero-bottom.png or swoop-0.png are slow loading, as they weight in at 2302 KB and 1611KB respectively. They're served with just 3 minute cache header, which means that the CDN will almost be a cache-miss. How much control do you have over the headers?
Converting images from png to webp or avif formats, there is some tiny loss of detail but one needs to be actively looking comparing what has changed, but this reduces the size by 4-8x times:
convert swoop-0.png swoop-0.webp #down to 461KB
avifenc swoop-0.png swoop-0.avif #down to 182KB
There are some nice tools showing the site load times and suggestions:
- PageSpeed analysis - load time 5 seconds
- WebPage test analysis - main site also 5 seconds, and subpage is 6.5 seconds