diff --git a/image/image.go b/image/image.go
index 4702919ab4..d9326fbd17 100644
--- a/image/image.go
+++ b/image/image.go
@@ -46,6 +46,9 @@ func New(root string) (*Store, error) {
 // Import creates a new image from the contents of `archive` and registers it in the store as `name`.
 // If `parent` is not nil, it will registered as the parent of the new image.
 func (store *Store) Import(name string, archive io.Reader, parent *Image) (*Image, error) {
+	if strings.Contains(name, ":") {
+		return nil, errors.New("Invalid image name: " + name)
+	}
 	layer, err := store.Layers.AddLayer(archive)
 	if err != nil {
 		return nil, err
@@ -62,6 +65,9 @@ func (store *Store) Import(name string, archive io.Reader, parent *Image) (*Imag
 }
 
 func (store *Store) Create(name string, source string, layers ...string) (*Image, error) {
+	if strings.Contains(name, ":") {
+		return nil, errors.New("Invalid image name: " + name)
+	}
 	image, err := NewImage(name, layers, source)
 	if err != nil {
 		return nil, err
diff --git a/server/server.go b/server/server.go
index 17dc7705c4..d52666d8f6 100644
--- a/server/server.go
+++ b/server/server.go
@@ -411,6 +411,9 @@ func (srv *Server) CmdPull(stdin io.ReadCloser, stdout io.Writer, args ...string
 	if name == "" {
 		return errors.New("Not enough arguments")
 	}
+    if strings.Contains(name, ":") {
+        return errors.New("Invalid image name: " + name)
+    }
 	u, err := url.Parse(name)
 	if err != nil {
 		return err
@@ -828,10 +831,13 @@ func (srv *Server) CmdRun(stdin io.ReadCloser, stdout io.Writer, args ...string)
 	img = srv.images.Find(name)
 	if img == nil {
 		stdin_noclose := ioutil.NopCloser(stdin)
-		if srv.CmdPull(stdin_noclose, stdout, name) != nil {
-			return errors.New("Error downloading image: " + name)
+		if err := srv.CmdPull(stdin_noclose, stdout, name); err != nil {
+			return err
 		}
 		img = srv.images.Find(name)
+		if img == nil {
+			return errors.New("Could not find image after downloading: " + name)
+		}
 	}
 
 	// Create new container