It's 2020.... PNG or SVG files for use as emoji/smilies?

[Kevin]

I just have a $5 VPS at Digital Ocean with LEMP on it. Graphics for the site and anything in the style folder is in it. I use a .net of my .com domain to point to it and I cache it though Cloud Flare. I would love to know how to do this with external_data too to cache attachments and avatars

At least in regards to emoji (not XF smilies), my journey was in regards to the "Emoji source". If you have emoji enabled on your site and if you're using JoyPixels or Twitter and if you've left the "Emoji Source" option at the default of "Server from preferred CDN" then it means that your emoji images are being served from a 3rd-party server and not your own. In the scenario you are describing, of wanting to minimize serving resources from a 3rd-party and/or using a cookie-less domain, then if you have emoji enabled then your "Emoji source" option should be the "Host from following location" to use your own specified location or your "Emoji style" should be Native so that only device specific emoji are used.

 

[ShikiSuen]

I personally prefer SVG simply because it can covers future needs for dozens of years.
P.S.: In some cases I admit that FontAwesome emoticons are enough.