It seems anytime an image isn’t used in a blog post (or when the image is too small), jetpack uses a header image in the sidebar as the image to send to facebook. This is of course not what I want at all. I’d rather no image gets sent at all.
When you share a post on Facebook, or when Jetpack Publicize publishes a post to your Facebook page, Facebook crawls the page and looks for Open Graph meta tags in the head to build a complete post preview (with an image, title, description, …).
Jetpack automatically creates these Open Graph Meta tags for you, and if your post doesn’t include any image, Jetpack includes a “blank” image instead, to force Facebook not to use a random image from somewhere else on the page:
https://wordpress.com/i/blank.jpg
That usually works, but looking at your site, I see 2 sets of Open Graph Meta tags; one is added by Facebook and includes the blank image, and the other is added by the WordPress SEO plugin I think:
https://i.wpne.ws/XzUC
Unfortunately Facebook doesn’t cope well with duplicate sets of tags on a page. It could cause it to ignore that blank image specified by Jetpack.
I’d consequently suggest that you stick with one set of tags only. You can disable WP SEO’s tags by going to SEO > Social in your dashboard.
@ralloux I’m afraid I can’t help without knowing your site URL. Could you post it here so I can take a look?
If you want it to remain private, you can also contact us via this contact form:
https://jetpack.me/contact-support/
