To manually publish your image go docker, you must follow this:
docker image list will show all the images you have, so check all the images and search for the one you just created
PS D:\git\mssql-samples-db> docker image list
REPOSITORY TAG IMAGE ID CREATED SIZE
mssql-server-samplesdb_db1 latest __IMAGE_ID_VALUE__ About a minute ago 2.06GB
Now that you have the IMAGE_ID you want to push to your docker image registry,
And now you can instantiate a container from the image:
docker tag 9e4b368a45e8 enriquecatala/mssql-server-samplesdb:2019-CU4-ubuntu-16.04
docker login
docker push enriquecatala/mssql-server-samplesdb