That 30 days is coming from the Cache-Control
header.
I would start looking at the configuration on your origin (the server behind Cloudflare (and not Cloudflare)) for that, as it may likely be that the server has been configured, to believe that the “.JPG
” is a static asset, and therefore is responding with a long-term Cache-Control
header.
Without any specific options for the “Browser TTL
” in Cloudflare, Cloudflare (as well as other CDN providers) will simply pass on what it receives from your origin.