`nix-prefetch-docker` command can be used to get required image parameters:
```ShellSession
$ nix run nixpkgs.nix-prefetch-docker -c nix-prefetch-docker --image-name mysql --image-tag 5
$ nix run nixpkgs#nix-prefetch-docker -- --image-name mysql --image-tag 5
```
Since a given `imageName` may transparently refer to a manifest list of images which support multiple architectures and/or operating systems, you can supply the `--os` and `--arch` arguments to specify exactly which image you want. By default it will match the OS and architecture of the host the command is run on.
