Your og:image is probably a 404.
The meta tag is in your HTML. The image isn't on your server. Every share of your site renders as a gray rectangle and nothing reports a problem.
Diagnostics
4 min read
We found this one on a client's site while building this portfolio. The homepage declares a social
preview image in its metadata. The file at that address returns a 404 with a content type
of text/html, which is the server handing back an error page where a picture should be.
Every link anyone has ever shared to that site rendered without a card.
Why nobody catches it
Because nothing breaks. The tag validates. The page loads. Search Console doesn't check it. Your analytics doesn't check it. The only symptom is that shares in Slack, iMessage, LinkedIn, and everywhere else render as a bare link, and you'd only notice if you shared your own site and looked closely.
How to check yours in 10 seconds
- Find the tag. View source and search for
og:image. Copy the URL out of the content attribute. - Open it directly. Paste it into a browser. You should see an image. If you see your homepage, your 404 page, or anything else, it's broken.
- Check the content type as well as the status. A server can return
200and still hand back HTML. If the content type isn't an image, no platform will render it.
The general lesson
The most expensive website faults are the quiet ones. Anything that fails loudly gets fixed in an afternoon. Anything that fails quietly, a missing preview, a font that never loads, a form that submits without recording, can run for years, and every one of them costs you something you can't see on a dashboard.
Not sure whether this is happening on your site?
We'll run the 5 checks on it and tell you, in plain English, whether or not you ever hire us.