GPLv2 compliance for third-party Docker images.

Hello everybody,

we redistribute GPLv2 software and comply with it by providing source
packages together with the binary ones.  This is why we do not have to
give a written offer to provide the source for 3 years.  (Please correct
me if I am wrong).

For my understanding, can somebody explain me how third parties building
and redistributing Docker containers including GPLv2 software comply
with the license when they do not give a written offer to provide the
sources for 3 years?

In my understanding, the GPLv3 solves that problem with its clause 6d,
which is why I am asking for the GPLv2 only…

Have a nice week-end,

Charles