You can generate image URLs for your sitemaps that use the customer content delivery network (CDN).
These image URLs consider the setting of Http Static CDN Root
as configured
in the Customer CDN Settings as
follows:
HTTP Static CDN Root
references an absolute CDN root (with the
host part), then it is always used for image URLs, and the host name setting of the
site map generation job is ignored.your.instance.hostname.example.com
is used.