images.tooling.report

Client-Hints

Respect Headers: Client-Hints?

a child looking into a telescope, pointed upwards

Introduction

Client Hints are a set of HTTP request header fields that a server can proactively request from a client to get information about the device, network, user, and user-agent-specific preferences. Ideally, image optimization tooling should be willing to modify their responses based on the result of these hints (i.e. serve smaller images to those on slower networks, etc).

The Test

Did the service include an accept-ch header in their response? If so, did it respond with differing content based on different inputs to the requested headers?

Conclusion

akamai
bigCartel
cloudflare
cloudinary

Cloudinary supports Client-Hints, if you manually enable them with flags like dpr_auto and w_auto.

ecwid
fastly
goDaddy
imageEngine
imaginary
imgix

imgix lets you manually set the Client-Hints you want to be dealt with by setting the ch parameter on the URL

documentation

imgproxy
optimole
shopify
shortPixel
smush
squarespace
thumbor
webflow
weebly
wix