diff --git a/INSTALL.md b/INSTALL.md
index 189ae192..40e167a2 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -241,6 +241,7 @@ tmp_file=$(mktemp)
     --attr-bold \
     --attr-italic \
     --attr-underline \
+    --sixel \
     ${tmp_file}
 ./pgo ${tmp_file} ${tmp_file} ${tmp_file}
 rm ${tmp_file}