No, latest is just a tag and is not handled differently. There is a CLI flag to ignore cached layers. This however does not effect the FROM line, so if you have the image, there will be no pull.

Expect this to effect CI systems

No they don't, but if you do something silly like spin up a bare VM build node, and then pull your environment every time, then obviously you won't get any caching.

Github Actions? Gitlab CI? Many of those don't do any caching because of the chance of poisoning a tag in the local registry, and don't have a good way to do caching per project.

I can imagine that this affects those sorts of operations.

Yeah, that's what I was getting at - in CI I can see it, but in local dev it would seem surprising to need more than the free-with-authentication quota.

That said, if your CI needs more, it's probably time to invest in a paid account if you can, and certainly if you're commercial.

You can use the GitLab Dependency Proxy for caching images from DockerHub, it's pretty straightforward to pull cached images:

https://docs.gitlab.com/ee/user/packages/dependency_proxy/

Using `docker-machine` You can use an environment variable to pull from a local docker mirror from new bare VMs.

`export ENGINE_REGISTRY_MIRROR=https://mirror.mysite.com`