Image in email alert with storage provider "local"?

@daniellee @torkel @mefraimsson
Images are not shown in Email Alerts

Grafana v6.3.6
SMTP : gmail (setup correctly I am getting test notification)
Image : Rendered
Image Provider : local ( not s3,…)
Image accessible from outside network: yes, from log i can get image url and its accessible
Grafana instance accessible from outside network : yes
Email : Receiving with text only, Image(broken icon) no image

Official Docs Says
" Be aware that if you use the local image storage email servers and clients might not be able to access the image."

So is it possible or not? Currently not attaching images for me.