diff --git a/pyproject.toml b/pyproject.toml
index e4e715f..3afe0d8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,7 +29,7 @@ dependencies = [
     "click",
     "Jinja2>=2.7",
     "Markdown",
-    "Pillow>=8.0.0",
+    "Pillow>=8.0.0,<10.0.0",
     "pilkit",
     "natsort",
 ]