Hi,

if you are using the social share plugin ensure to follow these best practices:

1. Enable the option 'Open Graph image detection', 'Open Graph title detection', 'Open Graph description detection' in plugin settings

2. Place an image as the first image in your Joomla articles. It could be even a hidden image using CSS such as style="display: none"

3. Check that in the source HTML code the image is added as the meta tag o:image like ths for example: <meta name="og:image" content="http://demo.storejextensions.org/jsitemap/images/headers/windows.jpg" />

4. Ensure that the image is valid to be accepted by FB share, for a post it must be an image having size 1200 x 628

5. Use the Facebook debugger to refresh the Facebook cache and test how FB crawl your pages https://developers.facebook.com/tools/debug/

6. Share at least 2 or 3 times on Facebook before getting the image accepted

7. Read the official FB best practices at https://developers.facebook.com/docs/sharing/best-practices and this guide for choosing optimal images for socials: https://www.rakacreative.com/blog/social-media-marketing/social-media-image-sizes-always-up-to-date/

Best regards

John