Meta info (OpenGraph) for link sharing

I noticed that when I post a link to on, there’s no rich display.

For example, here it works (if I post a raw URL):

But on Mastodon, the image is missing?

If I remember my OpenGraph correctly, this may be because there’s no og:type listed in the page - I don’t think these three tags are sufficient for many implementations to render a preview (I know that certainly is not enough for Twitter cards, I’m guessing that’s also true on Mastodon); or, there’s something weird going on with image fetching between and the CDN, but that seems less likely to me.

<meta property="og:title" content="@andypiper on">
<meta property="og:description" content="Eurasian Jay on our #BirdBuddy">
<meta property="og:image" content="">

Hmm, this is baffling. I added og:type but it didn’t seem to help — the opengraph checker website that I use doesn’t have any issue, but Mastodon is still being stubborn. I’ll keep poking at it and hopefully will figure out the right magic combination of stuff to make it work.