You want to share your website on Facebook, and you want to specify what image and description is shown in the news feed or wall area.
To specify a thumbnail on Facebook you will need to do these two things.
- Use images that are at least 1200 x 630 pixels for the best display on high resolution devices. At the minimum, you should use images that are 600 x 315 pixels to display link page posts with larger images. Images can be up to 8MB in size.
- Upload the image
Create an Image
Facebook recommends that you use an image of at least 1200x630 pixels.
NOTE: This is quite large! Only JPG images are supported at this time. See:https://developers.facebook.com/docs/sharing/best-practices
Upload the Image
When you have your image ready, you can upload it from your admin area at Website -> Settings -> Facebook Share Image. Also at Website -> Settings, review the Description text field. This is the text that will be shown on Facebook when users share the page. This field is limited to 500 characters.
After you have uploaded the Facebook image, users clicking on the Facebook Share link will create a news story with a link to the participants page, which will show the uploaded icon.
DEBUGGING AND TROUBLESHOOTING
- You can confirm how Facebook sees your page by using their debugger found at https://developers.facebook.com/tools/debug/og/object/
- The first time you test the share link/icon, the uploaded image may not be immediately visible. This is because Facebook needs to scan the page and resize the image first. Try to reload the page, and share after a few minutes to confirm.
- If you ask Facebook to scrape your site URL as above, you will see exactly which image will be shown, and how the site is seen by Facebook. In particular, see how the og:image tag is being shown. This is what users will see when sharing the site.