Troubleshooting issues with suggested media and link details

When you paste a link into the Buffer composer, we’ll scan the page and suggest images and metadata (like title and description) for your post. If your link preview isn't looking quite right, this guide explains how Buffer pulls in that information, how you can optimize your site, and how to troubleshoot any issues.

In this article:

How Buffer finds images from URLs
What metadata does Buffer use to generate link previews?
How to validate your link
Common errors with sharing links and how to fix them

How Buffer finds images from URLs

When you add a link to the Buffer composer, Buffer uses a scraper to scan the page for images and then suggests them to use with your post. Here’s how it works:

The scraper checks for Open Graph tags (like og:image ) in the HTML.
It then scans the first 24 images, in groups of 8, until it finds at least 5 that meet certain requirements.
Only the first 15 valid images will be considered for Suggested Media.
Buffer checks that each image has a width or height attribute and that the image is large enough (at least 200x200 pixels) and reasonably square.

If the first 8 images are valid, Buffer stops there and uses those as the Suggested Media. This keeps things efficient and fast.

Tip: A properly formatted image might look like this:

  <img src="link-to-your-image" width="600"/>

What metadata does Buffer use to generate link previews?

Open Graph images first: The scraper checks for Open Graph tags (like og:image, og:image:secure_url, og:image:url) and Twitter Card images (twitter:image, twitter:image:src) in the HTML.
Article images: It prioritizes images within <article> tags or elements with itemprop="articleBody".
General page images: It then scans other images on the page.
Batch processing: The scraper processes up to 24 images total in batches of 15, until it finds at least 5 that meet the quality requirements.

We recommend following the Open Graph Protocol when setting up your website so that Buffer (and other platforms) can pull the correct information.

How to validate your link

To check what metadata is available for your link, we suggest using the Facebook Sharing Debugger or Buffer's scraper debugging tool.

Paste your URL there to:

See which metadata is available
Confirm which images are being pulled
Refresh Facebook's (and Buffer’s) cached version of your link

📝 Please note, these guidelines are for those who are sharing links to pages that they own and have control over. If you are sharing links to websites that you do not own, it is not possible to control which images are pulled in.

In some instances, Buffer's scraper can be prevented from accessing the information for the site to generate a link attachment. This can be due to the site's security configurations or the robots.txt. In both instances, Buffer will need to be explicitly allowed. You can find the information needed to create the rule, exception, or allowance here.

If you see the error, FetchError: request to [your URL here] failed, reason: unable to verify the first certificate - UNABLE_TO_VERIFY_LEAF_SIGNATURE,your website admin might need to update the SSL certificates as the website server is not correctly presenting the full SSL certificate chain. To resolve this, ask the website owner or admin to try to get SSL certificate up to date.

Best practices for optimizing your site for Buffer

Here are a few tips to ensure Buffer can pull the correct content from your links:

Add proper Open Graph tags to your HTML (og:title , og:description , og:image )
Place your og:image tag near the top of your page’s HTML
Use valid image formats and recommended sizes
Avoid blocking bots like Buffer’s in your firewall or server settings
Test and refresh your link using the Facebook Sharing Debugger

Still need help?

If you've tried the suggestions above and things still aren’t working as expected, feel free to reach out to us at hello@buffer.com — we're always happy to help!