The email shows the correct code:
<td class="vmdoc-header-image" width="50%"><img src="https://modernmagic5.sg-host.com/images/stories/virtuemart/vendor/retaildisplayusa1.jpg" style="width: 60mm;" /></td>
and the file exists: https://modernmagic5.sg-host.com/images/stories/virtuemart/vendor/retaildisplayusa1.jpg
Why is the logo not appearing in the order confirmation email?
images blocked by your email client?
You have problem with https on your domain :)
Fix it and then you see your vendor logo in email.
SSL issue has been resolved. Thanks the logo appears correctly now.