Sharing a property to Facebook or LinkedIn has several requirements:
1200x630pixels for the best display on high resolution devices. At the minimum, you should use images that are
600x315pixels to display link page posts with larger images.
When content is shared for the first time, the Facebook or LinkedIn crawler will scrape and cache the metadata from the URL shared. The crawler has to see an image at least once before it can be rendered. This means that the first person who shares a piece of content won’t see a rendered image. The same happens if the image has changed or is not available.
There are three ways to avoid this and have images render on the first Like or Share action:
og:image:heightOpen Graph tags: Using these tags will specify the image dimensions to the crawler so that it can render the image immediately without having to asynchronously download and process it.
We cache all images referenced based on each image’s URL, so if you replace an image:
Note that updating the image for a URL will not automatically update the preview for old shares. To do this, you must refresh the share as described here.
If you have any problems with images not being displayed correctly for a URL, try plugging in the image URL in the Sharing Debugger for any errors.