advancedDocker Registry & Image Distribution: Tagging, Versioning, Push & Pull

What's the difference between pulling an image by tag versus by digest?

A tag is a mutable pointer that can be repointed to a different manifest by a later push; a digest (content hash) always refers to one exact, immutable set of bytes — pulling by digest guarantees you get the identical image every time, while pulling by tag depends on whatever that tag currently points to.

Ready to master this question?

Generate a complete walkthrough — background, the full answer in plain language, a working code example explained line by line, a real-world scenario, common mistakes, and how this same question gets asked in different ways.

Next Step

Continue to Why does pushing a small code change to an image that shares a base with a previous version upload quickly? →← Back to all Docker questions