Why Does Docker Prepare, Wait, and Push So Many Images?

When I push an image to my container registry, there is quite a bit of output. Here is some from my recent push:

$ docker push example.com:4567/path:tag
The push refers to repository [example.com:4567/path]
efdef3353b03: Preparing
549310fd9b8e: Preparing
5f2c9c0ded0f: Preparing
61f73cf1df2d: Preparing
088a3da6fb36: Preparing
802a84a32a1c: Preparing
29778035860f: Preparing
fc88d2431f4d: Preparing
1dc1b82fa010: Preparing
09e3fd9cf357: Preparing
138d1921c15b: Preparing
d714f65bc280: Preparing
fd6060e25706: Preparing
d7ed640784f1: Preparing
1618a71a1198: Preparing
802a84a32a1c: Waiting
fd6060e25706: Waiting
d7ed640784f1: Waiting
29778035860f: Waiting
1618a71a1198: Waiting
09e3fd9cf357: Waiting
138d1921c15b: Waiting
1dc1b82fa010: Waiting
088a3da6fb36: Layer already exists
549310fd9b8e: Pushed
29778035860f: Layer already exists
802a84a32a1c: Layer already exists
1dc1b82fa010: Layer already exists
efdef3353b03: Pushed
138d1921c15b: Layer already exists
d714f65bc280: Layer already exists
fd6060e25706: Layer already exists
5f2c9c0ded0f: Pushed
d7ed640784f1: Layer already exists
fc88d2431f4d: Layer already exists
61f73cf1df2d: Pushed
09e3fd9cf357: Layer already exists
1618a71a1198: Layer already exists

Does this happen to anyone else? What is the cause?

These are all of the tags that are associated with that image. Each time you push, it will check to see if the updated images has any new tags and pushes accordingly. What does it look like in the UI? Or if you run docker image ls from the client?