Another approach (avoiding subscriptions and an additional layer of proprietary url-scheme) is just to use Markdown links preceded by a bang, in the ![image name](image url)
pattern.
Viewing a Bike file in marked2app.com will already display inline images included in the form of such links.
I personally harvest the Markdown link using this Keyboard Maestro macro, which automates it for a number of macOS applications, including the Finder: