Publicize correctly fetches pictures on Twitter and Google but not on Facebook

Hi David! 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 unless you already use another Open Graph plugin, in which case we let the other plugin handle things.

Jetpack’s Open Graph Meta Tags will use your post’s Featured Image, but only if it’s big enough (200x200px). If you do use our tags, and the featured image still doesn’t appear on Facebook, I’d recommend checking what Facebook sees when crawling your post by using the Facebook Debugger:
https://developers.facebook.com/tools/debug/

Let me know what you find! If you still experience trouble, can you point me a couple of Facebook posts that you believe aren’t using the right image? I’ll take a look to see if I can find out why for you.

Hi Ryan, thanks a lot for the feedback!

I was aware of these limitations, and the problem on Facebook came from the absence of featured image, since the post was only made of a series of pictures.

However, both Twitter and Google+ did compensate for the lack of a featured image by picking the last image of the series (or an image at random, I did not remember) to illustrate the post.

Could this fallback mechanism be also used by JetPack Publicize for Facebook? This would be very useful since some users experience difficulties with WordPress complexities (in comparison with more “mass-market” blogging platforms) such as remembering about the featured image…

BTW, what happens when someone uses JetPack “Post by email” option, adds pictures in attachment of the email but does not specify a featured image? The same issue shows up?

What do you think? Thanks in advance for your help!

Post-scriptum: Ryan, I have some extra feedback for you…

I think I spotted the issue: when submitting my link to the Facebook Debugger, I got this warning:

Provided og:image URL, https://repaircafemarseille.fr/wp-content/uploads/IMG_4511-600x450.jpg could not be downloaded because it exceeded the maximum allowed sized of 8Mb.

Therefore, there seems indeed to be some kind of fallback mechanism when no featured image is available, as on Twitter and Google+ (see my previous post).

However, there seems also that there is a bug somewhere: Facebook complains about an image that is too big but the link mentioned in the warning refers to a very light image.

BTW, if you want to check the original image, you can find it in the media library of the website.

What do you think? Thanks again!

Hi there! Jetpack does indeed fallback to another image in your post if a Featured Image is not set.

I had a look at the post you linked to, and I noticed that there are multiple og:image values specified in the source. A lot of these images are indeed bigger in filesize. Could you try either setting a Featured Image that is smaller, or uploading smaller images to your posts? Then, see if the issue persists.

Please let me know how that goes!

Hi Ryan, thanks a lot for the extra feedback! If I sum up the constraints for JetPack Publicize, in order for it to work on Facebook (Twitter and Google+ seems to be fine without those constraints):

• post image dimensions should be larger than 200 x 200 pixels;
• post image weight should be smaller than 1MB (Facebook error message says 8Mb)

Since I have not uploaded these images myself and they are currently 3MB large (a default size apparently) I will ask the author to provide a seriously downsized version of these, following the previous constraints. I will let you know if it still does not work.

My two cents: do you think these constraints could be explicitly stated on the media library upload interface when the JetPack Publicize plugin is activated? This would help immensely users like me figure out why things are not working as expected… ??

Thanks in advance for your help!

Post-scriptum: Ryan, again, I have omitted important pieces of information… My apologies for this.

In fact, the JetPack Publicize problem was not showing up on the blog post of another batch of photos (3MB each) that we published using a JetPack Gallery. Therefore, I did the same with this new batch, and suddenly Facebook warning disappeared and the post sharing window displayed a picture…

What do you think?

Thanks for the update! It’s worth noting that the 8mb filesize limit comes from Facebook. Jetpack will accept any featured image and set it as the og:image tag, but Facebook may not use that image if it exceeds their limits. As such I’d recommend resizing and saving your images for web before uploading them to your posts.

I hope that helps clear things up! Let me know if you have any other questions.

Thanks Ryan for your help! Everything is fine now. I close this thread.