One of WhatsApps most current privacy-related features is vanishing messages, which is currently readily available on Android and its coming actually soon for iOS users. The feature is apparently being evaluated on a beta variation of the app but it definitely wont take long prior to it hits the final version of IOS.
Screenshots from the new beta version of the app
Theres a dedicated timer in the caption input field when sending out media and the sender gets a notification once the recipient has seen the photo/video message. Theres nothing stopping the recipient from taking a screenshot before the message disappears.
The disappearing messages isnt about texts only. The disappearing text messages, on the other hand, take 7 days prior to they disappear.
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