When you build Docker images many times, you will find it is very necessary to manage images with tags.
If you build an image without a tag, the default tag 'latest' is created automatically.
docker build -t company/myimage .
The complete name is company/myimage:latest
When you need to update a new version of company/myimage, you don't need to create an image company/myimage_v2. You should create an image with the same name and a new tag.
docker build -t company/myimage:v2 .
And set it latest
docker tag -f company/myimage:v2 company/myimage:latest
So your new image has two tags: v2 and latest. When you start a container based on company/myimage, company/myimage:latest will be used.