diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 4fb1153..87afc4f 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -40,3 +40,5 @@ jobs:
 
     - name: Run test suite
       uses: php-actions/phpunit@v4
+      with:
+        php_extensions: gd