Use images.weserv.nl to cache your images on your ghost blog
git clone on your content/apps/ folder
go to content/apps/ghost-weserve-helper
run: nodejs install.js (it will update active_apps in DB)
restert ghost ghost restart
In your template, you can now write:
{{weserv "https://gkdv.net/content/images/2018/02/gkdv-1.png"}}