A link preview in WhatsApp
When a link is sent on WhatsApp, the preview is taken from Open Graph tags: title, description, and image. Without an image of a reasonable size the preview is empty or broken. This is not an ad. It is the card of the page.
Three tags
og:title is the card title. og:description is the line under it. og:image is the file. They can match the Google title and description, or be aimed more at sharing. They do not replace them.
The image has to load from a full https address, not a broken relative path. A huge file also slows the fetch WhatsApp makes. After a change, the preview cache has to be cleared, because WhatsApp keeps an old card.
| Tag | Job | Failure |
|---|---|---|
| og:title | The card title | Empty, or a file name |
| og:description | One line | A whole paragraph cut mid-word |
| og:image | The picture | An address that does not open, or a megabyte |
| og:url | The canonical address | An old preview URL |