Why does WhatsApp backdate images?

Question

Android

When you send or receive images on WhatsApp, the app saves them to a separate WhatsApp Images folder with a name like "IMG-20190629-WA0000.jpg". It would be logical to assume that this is the date the message was received (sent). At worst - the date of download to the device. But no, sometimes this date can even be much earlier than the date the snapshot was taken.
Example:

The files "IMG-20190629-WA0000.jpg" and "IMG-20190619-WA0001.jpg" have exactly the same content, but in the second case, the picture is dated 10 days earlier than it was taken. The date on the phone was not translated, roaming was not turned on, the limits of the sentry did not leave. This bug is observed quite often. The displacement does not always occur in one direction.
Why can this be and how can you determine which of the two dates is real, if you do not know this in advance?
PS The most interesting thing is that the system file creation date is also 10 days behind the event!

Answer 1

There is no visible or documented system for naming media files in WhatsApp. It is recommended not to try to work with pseudo-dates in names.