It’s a feature that deletes photos or videos from your chat after they’ve been opened by the recipient
The recipient will be able to see that it’s a disappearing photo, so it’s still the type of thing you’d only want to use for people you trust to not take a screenshot.
How it works:
When sending a photo or video via WhatsApp and have it expire, click the “1” button to the left of the send button.
The content will expire once the recipient has opened it, and they will be notified that it isn’t a permanent pic – so ensure it’s nothing too secret, as they can still screenshot it.