The sizes are all listed on docker hub, see https://hub.docker.com/r/couchbase/operator/tags for example. The couchbase/operator part is the name of the image you supply in your configuration, so you can substitute it for couchbase/server.
While on that topic there are no data/query images, they are all the same Server image.
Finally, the images are stored by docker (or whatever container technology you are using) on each Kubernetes nodes they are/have ever been run on. Look at their documentation for more details as to the storage and format of container images.