Hi there,

By default they will be stored in the /var/lib/docker/driver_name directory. The driver_name directory would depend on the driver that you are using.

What I usually would do is to always use the following command to verify the data directory:

docker info | grep -i 'Data file'

I would also recommend taking a look at the following two answers for more information:

• How to move the default /var/lib/docker to another directory for Docker on Linux?
• How to check the disk usage of all running Docker containers?

Hope that this helps!
Regards,
Bobby