The 'Delete for all' function does not delete the images that have been downloaded to an iPhone, something that they do by default.
Although it has been more than a year since WhatsApp introduced a tool to delete messages, the function still has a bug that makes the photos and videos that iPhone users receive cannot be deleted from their galleries. Despite this, the person who sent the photo and then believes they have deleted it, will see instead the phrase "This message was deleted".
The flaw was discovered by a security consultant, who reported this to Hacker News, and it can be easily verified. Indeed, although the option is called 'Delete for all', the photograph continues in the user's camera if the user had downloaded it before. It should also be remembered that the function can only be used for up to one hour, eight minutes and 16 seconds from delivery.
Added to this is the problem that WhatsApp downloads images automatically by default, so in many cases it will have been saved. In the case of Android it does work even if the file has been stored, so this aspect is not a problem.
Although the flaw is due to a limitation that makes sense (allowing an app to make changes to files saved in the gallery without your consent can be very problematic), WhatsApp confers a false sense of security by ensuring that the message has been removed.
The company, for its part, defended itself through a spokesperson and assured The Hacker News that the tool "works correctly" since using it removes the file from the conversation and that once in the gallery of an iPhone user, it remains out of reach.