Serving pictures efficiently.
WHAT CLOUDFLARE DOES BY DEFAULT
Caches images at the edge, so repeat requests do not reach us.
That reduces bandwidth and speeds delivery. It does not make the images smaller.
WHAT IT DOES NOT DO ON THE FREE PLAN
Resize, compress or convert formats. Those are paid features.
WHAT ACTUALLY MATTERS MOST
Optimising images before they are served: resizing to the dimensions needed, compressing, and using modern formats.
A four megabyte photograph cached at the edge is still four megabytes to the visitor.
DOING IT PROPERLY
Resize before uploading Use an optimisation plugin that compresses on upload Serve modern formats where supported Enable lazy loading
THE ORDER OF PRIORITY
Optimise the images. Then cache them.
Caching unoptimised images improves delivery and leaves the file size problem untouched, which is what visitors on mobile data actually notice.
FOR MEDIA-HEAVY SITES
Consider object storage with its own delivery, which separates media entirely from your hosting account.