In case you are not familiar with caching definition, here is what means s-maxage :
s-maxage ('s' means seconds) — Indicates that in shared caches, the maximum age specified by this directive overrides the maximum age specified by either the max-age directive or the Expires header field. The s-maxage directive also implies the semantics of the proxy-revalidate response directive. Browsers ignore s-maxage
The cache expiration period is controlled by the s-maxage directive.
In short, there are 3 types of servers that participate in this process:
- CDN servers - their main purpose is to cache the Cloudimage processed images and to deliver them to the final users
- Cloudimage servers - they optimise your original images
- Origin server - it stores the original image files
We suggest you to read the following articles:
If you have any further questions, do not hesitate to contact our Support team.