​@Wen could you possibly provide screenshots of what you are experiencing?

Clarify also if the image url is taken from the viewed product event or catalog tag lookup.

It could either be attributed to styling in the email or if the image url is firewalled.

Yes ​@whereisjad , I used the image URL and the image shows correctly in preview, but when I tested it, there’s no image at all.

This is the event properties example.

​@Wen thanks for sharing.  here's a suggestion, could you try pre-pending to the image url "https:" 

I highly suggest email is nitpicky about formatting while preview is lax which is why it worked one place but not the other.