You can use clusterctl to list the images used by Cluster API and the Cluster API provider in use:
clusterctl init list-images --infrastructure <infrastructure-provider>
For more details see: https://cluster-api.sigs.k8s.io/clusterctl/commands/additional-commands.html#clusterctl-init-list-images
See our general list of mirroring options
To use Cluster API with mirrored images, you can configure clusterctl to use image overrides.
For more details see: https://cluster-api.sigs.k8s.io/clusterctl/configuration.html#image-overrides