diff --git a/cmd/compose/convert.go b/cmd/compose/convert.go
index 91c8e3bb..68d0f77a 100644
--- a/cmd/compose/convert.go
+++ b/cmd/compose/convert.go
@@ -224,7 +224,7 @@ func runConfigImages(opts convertOptions, services []string) error {
 		if s.Image != "" {
 			fmt.Println(s.Image)
 		} else {
-			fmt.Printf("%s_%s\n", project.Name, s.Name)
+			fmt.Printf("%s%s%s\n", project.Name, api.Separator, s.Name)
 		}
 	}
 	return nil