diff --git a/pkg/crane/digest.go b/pkg/crane/digest.go
index 8a4358773..7fa774b6f 100644
--- a/pkg/crane/digest.go
+++ b/pkg/crane/digest.go
@@ -25,6 +25,8 @@ func Digest(ref string, opt ...Option) (string, error) {
 		if !desc.MediaType.IsIndex() {
 			return desc.Digest.String(), nil
 		}
+
+		// TODO: does not work for indexes which contain schema v1 manifests
 		img, err := desc.Image()
 		if err != nil {
 			return "", err