@@ -1,6 +1,7 @@

 package docker

 import (

+	"crypto/sha256"

 	"encoding/json"

 	"fmt"

 	"github.com/dotcloud/docker/rcli"

@@ -695,6 +696,18 @@ func (container *Container) ExportRw() (Archive, error) {

 	return Tar(container.rwPath(), Uncompressed)

 }

+func (container *Container) RwChecksum() (string, error) {

+	h := sha256.New()

+	rwData, err := container.ExportRw()

+	if err != nil {

+		return "", err

+	}

+	if _, err := io.Copy(h, rwData); err != nil {

+		return "", err

+	}

+	return string(h.Sum(nil)), nil

+}

+

 func (container *Container) Export() (Archive, error) {

 	if err := container.EnsureMounted(); err != nil {

 		return nil, err

@@ -98,11 +98,13 @@ func (graph *Graph) Create(layerData Archive, container *Container, comment, aut

 		img.Parent = container.Image

 		img.Container = container.Id

 		img.ContainerConfig = *container.Config

-		if config == nil {

-			if parentImage, err := graph.Get(container.Image); err == nil && parentImage != nil {

-				img.Config = parentImage.Config

-			}

+		// FIXME: If an image is pulled from a raw URL (not created from a container),

+		// its checksum will not be computed, which will cause a push to fail

+		checksum, err := container.RwChecksum()

+		if err != nil {

+			return nil, err

 		}

+		img.Checksum = checksum

 	}

 	if err := graph.Register(layerData, img); err != nil {

 		return nil, err

@@ -18,6 +18,7 @@ import (

 type Image struct {

 	Id              string    `json:"id"`

 	Parent          string    `json:"parent,omitempty"`

+	Checksum        string    `json:"checksum,omitempty"`

 	Comment         string    `json:"comment,omitempty"`

 	Created         time.Time `json:"created"`

 	Container       string    `json:"container,omitempty"`