Do not cache image handler.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/store/image/image.go

@@ -47,8 +47,6 @@ type Image struct {
 	Size int64
 	// ImageSpec is the oci image structure which describes basic information about the image.
 	ImageSpec imagespec.Image
-	// Containerd image reference
-	Image containerd.Image
 }
 
 // Store stores all images.
@@ -152,7 +150,6 @@ func getImage(ctx context.Context, i containerd.Image) (*Image, error) {
 		ChainID:    chainID.String(),
 		Size:       size,
 		ImageSpec:  ociimage,
-		Image:      i,
 	}, nil
 }