private List<ImageConfiguration> getAllImages() {
        List<ImageConfiguration> allImages = new ArrayList<>();

        if (images != null) {
            allImages.addAll(images);
        }
        if (imagesMap != null) {
            imagesMap.forEach((alias, config) -> {
                if (config.getAlias() == null) {
                    config.setAlias(alias);
                }
                allImages.add(config);
            });
        }
        return Collections.unmodifiableList(allImages);
    }
Get all volumes which are defined separately from the images

@return defined volumes
src/main/java/io/fabric8/maven/docker/AbstractDockerMojo.java