I would strongly suggest serving this landing page via http/2.0 - your 504 requests over http/1.1 are currently taking 3.5 minutes for me to load 2MB of data.
Using 500 requests for this because http2 exists is like stating it's ok electron apps eat 1 Go of ram because we have big configs today.
That's also why, in 2019, with quad cores, SSD and more memory than ever, things doesn't feel faster than 10 years ago.
https://gist.github.com/4lejandrito/6d4f903e0a692b87344e8600...
The resize function only resizes the first time and uses a cached version of the image after that.
I checked the server and the CPU is not too high so I think it must be HTTP as parent pointed out.
Ignore my comments, then.
For now I am just disabling the background samples so that only 1 creepyface is loaded per user. Should be ready in a few minutes.
For testing it in the browser: in Chrome at least, the developer tools Network tab details the protocol of each request/response. I believe Firefox has similar functionality.