When migrating from oc-mirror v1 to v2, images listed under additionalImages without an explicit registry hostname are mirrored to incorrect target paths.

In oc-mirror v1, image parsing relied on OpenShift’s library-go, which automatically defaulted missing registries to docker.io, preserving consistent namespace structure. 
- Ref: https://github.com/openshift/oc-mirror/blob/main/pkg/image/resolve.go 

In oc-mirror v2, parsing now uses the upstream go-containerregistry library, which follows stricter OCI standards — it no longer defaults to docker.io and instead treats the first path component as a potential registry, leading to different mirroring behavior for images without explicit hostnames.

- https://github.com/openshift/oc-mirror/blob/main/v2/internal/pkg/image/image.go#L51 

The above function returns:

1] additinalImages:
    - docker.io/netapp/trident-autosupport:25.02

--> imgSpec.Domain = "docker.io"
    imgSpec.PathComponent = "netapp/trident-autosupport"  <---

2] additionalImages:
    - netapp/trident-autosupport:25.02 

--> imgSpec.Domain = "netapp"
    imgSpec.PathComponent = "trident-autosupport" <---