diff --git a/build_library/build_image_util.sh b/build_library/build_image_util.sh
index 8502d1ebf2..434bc0f8ed 100755
--- a/build_library/build_image_util.sh
+++ b/build_library/build_image_util.sh
@@ -12,9 +12,9 @@
 # Use canonical path since some tools (e.g. mount) do not like symlinks.
 # Append build attempt to output directory.
 if [ -z "${FLAGS_version}" ]; then
-  IMAGE_SUBDIR="${COREOS_VERSION_STRING}-a${FLAGS_build_attempt}"
+  IMAGE_SUBDIR="${FLAGS_group}-${COREOS_VERSION_STRING}-a${FLAGS_build_attempt}"
 else
-  IMAGE_SUBDIR="${FLAGS_version}"
+  IMAGE_SUBDIR="${FLAGS_group}-${FLAGS_version}"
 fi
 BUILD_DIR="${FLAGS_output_root}/${BOARD}/${IMAGE_SUBDIR}"
 OUTSIDE_OUTPUT_DIR="../build/images/${BOARD}/${IMAGE_SUBDIR}"