Over 600 small pictures are loaded. How to optimize them?

Question

Images

There is a page on which more than 600 images are loaded, or rather site favicons (mostly png).
At first I pulled images through Google in the format " https://s2.googleusercontent.com/s2/favicons?domai... ", the page loaded slowly due to the large number of requests to Google. Sometimes even Google blocked the download.
I decided to upload pictures to my server and upload them from myself. Then I realized that I made a mistake when I uploaded 250 pictures. Now these pictures are pulled from my server, increasing not only the load (by requests), but also increasing the page size (by the size of the pictures).
The site has become even slower to load. I stopped with the idea of ​​"throw everything to yourself" and left the second part "download from google".
Question. How can they be optimized? Reduce the number of requests, increase the speed of loading the site.
Sprites are not suitable, because there are too many pictures, and I add new services often.
There are options?

Answer 1

you put it on a subdomain, better on subdomains:
0.fi.domain.com
... 123456789ABCDE...
F.fi.domain.com
and cache subdomains through Cloudflare

Answer 2

In vain you so at once refuse sprites. Sprites can be generated on the server side as needed. For example in PHP