Dangling Image is an untagged image that isn't referenced by any container.
This happens when image lost its association with any tagged image. An example of this case is building a new image with the same tag as an existing image.
Dangling images have no tag and it's shown as `<none>:<none>`
```
REPOSITORY TAG IMAGE ID CREATED SIZE
<none> <none> dacb7133d988 13 days ago 1.54GB
```
### See also
1. [[How to list all dangling images in Docker?]]
### Reference
1. [Docker Website](https://docs.docker.com/engine/manage-resources/pruning/)