diff --git a/bin/compose-core b/bin/compose-core
index 6e988f8..726f067 100755
--- a/bin/compose-core
+++ b/bin/compose-core
@@ -383,7 +383,7 @@ docker_has_image() {
         err "docker images call has failed unexpectedly."
         return 1
     }
-    [ "$images" ]
+    [ -n "$images" ]
 }
 export -f docker_has_image