I'm using Salesforce Files with enhanced letterheads with a URL like the following:
<img alt="Company_letterhead_header" src="https://my-domain--c.na191.content.force.com/file-asset-public/Company_letterhead_header?oid=00DU0000000LQa7".../>
I'm concerned that this URL is brittle because of the hardcoded SF instance (na191). Will this instance number change and break my letterheads? I've tried using data URI's and base64 image encoding but, like anything but very simple html, Salesforce lightning flags this an an error in the enhanced template editor (no problem rendering it though): I also looked into using svg images but they are not well-supported by email clients. If this URL is brittle, what should I be doing, other than hosting the images on a different content delivery network?
Thanks in advance for any advice.