@@ -273,7 +273,7 @@ func (graph *Graph) Delete(name string) error {

 // Map returns a list of all images in the graph, addressable by ID.

 func (graph *Graph) Map() (map[string]*Image, error) {

 	images := make(map[string]*Image)

-	err := graph.WalkAll(func(image *Image) {

+	err := graph.walkAll(func(image *Image) {

 		images[image.ID] = image

 	})

 	if err != nil {

@@ -282,9 +282,9 @@ func (graph *Graph) Map() (map[string]*Image, error) {

 	return images, nil

 }

-// WalkAll iterates over each image in the graph, and passes it to a handler.

+// walkAll iterates over each image in the graph, and passes it to a handler.

 // The walking order is undetermined.

-func (graph *Graph) WalkAll(handler func(*Image)) error {

+func (graph *Graph) walkAll(handler func(*Image)) error {

 	files, err := ioutil.ReadDir(graph.Root)

 	if err != nil {

 		return err

@@ -306,7 +306,7 @@ func (graph *Graph) WalkAll(handler func(*Image)) error {

 // If an image has no children, it will not have an entry in the table.

 func (graph *Graph) ByParent() (map[string][]*Image, error) {

 	byParent := make(map[string][]*Image)

-	err := graph.WalkAll(func(image *Image) {

+	err := graph.walkAll(func(image *Image) {

 		parent, err := graph.Get(image.Parent)

 		if err != nil {

 			return

@@ -328,7 +328,7 @@ func (graph *Graph) Heads() (map[string]*Image, error) {

 	if err != nil {

 		return nil, err

 	}

-	err = graph.WalkAll(func(image *Image) {

+	err = graph.walkAll(func(image *Image) {

 		// If it's not in the byParent lookup table, then

 		// it's not a parent -> so it's a head!

 		if _, exists := byParent[image.ID]; !exists {