Since Podman has a docker-daemon: transport that fetches from Docker, this is a straightforward loop over the images in Docker:

# select the images you want to import
docker images --format '{{.Repository}}:{{.Tag}}'
 
# import it to podman images
podman pull docker-daemon:IMAGE_NAME

Source: https://qulogic.gitlab.io/posts/2019-10-20-migrating-to-podman