Social media services like Facebook will attempt to select a featured image from news articles or posts on blogs. The automated selection process will give preference to larger images toward the top of an article or post.
In WordPress there is an option to have a Featured Image for your post. If the image is of adequate size and proper dimensions, then it should be used by Facebook, Twitter or other social media services. There may be situations where the image is too small or problematic dimensions so another image will be used. So, be sure to use a large image for your selected image.
Correcting Featured Image Issues
If you have a problem with your desired featured image, you can change it, but you will need to have Facebook rescan the original article you are sharing on Facebook. To do so, follow these steps:
- Update your WordPress post image to be larger and 4:3 or 16:9 in dimensions. Examples would be an image that is 1920 x 1080 pixels or 1280 x 720 pixels. You can also choose an image that is square. A preferred size should be 1000×1000 or larger.
- Go to Facebook Sharing Debugger here https://developers.facebook.com/tools/debug/
- On that page, paste in the URL (web page address) for the post you are working with.
- Click on the Debug button.
- You will see the image that Facebook currently has cached for that post.
- When you click on the Scrape Again button, Facebook will check the post again to see if there is a new image that can be used.
- The new featured image that Facebook has identified from your post will show up further down the page.