Debugging a toot image preview that is not loading

The image preview for links to our site are not working, and I’m not sure how to go about debugging it.


For that page, I have the following image related meta tags set:

<meta property="og:image" content="">
<meta property="og:image:secure_url" content="">
<meta name="twitter:image" content="">

But the image preview is not appearing in Mastodon…could someone help explain (or point me to documentation) on how image previews work in Mastodon? And what could be going wrong here? Is there a debugger tool or something I can use for this process?

This is the example link I’m trying to get to work Todd Cochrane CEO of Blubrry Podcasting and Rob Greenlee CEO

The content-type of your image is incorrect: it’s application/octet-stream rather than set to be image/jpeg or similar.

Hope that helps!


This could be caused by an old version of ImageMagick or whatever Ruby module called paperclip uses these days

Thanks @jamescridland! You are correct, the content-type was the problem. After changing the content-type to image/jpeg and image/png accordingly, the image previews began rendering properly.

In case someone lands here with toot preview card issues, the documentation can be found here.