Introduction
what
The Test
no
Conclusion
akamai
bigCartel
cloudflare
cloudinary
ecwid
fastly
goDaddy
imageEngine
imaginary
imaginary
Imaginary's built in server and offical docker image does not provide ETags, but you can add them but utilizing a reverse proxy in production.
imgix
imgproxy
optimole
shopify
shortPixel
shortPixel
ShortPixel Image Optimizer (the plugin being tested) serves images from your own WordPress server, it is up to you to serve it via HTTP2+. Therefore, this is not applicable. ShortPixel does have an API that does set an ETag Header.
smush
squarespace
thumbor
webflow
weebly
wix