diff --git a/.github/workflows/optimize-images.yml b/.github/workflows/optimize-images.yml
index 0fd4aa8..4d5eac2 100644
--- a/.github/workflows/optimize-images.yml
+++ b/.github/workflows/optimize-images.yml
@@ -15,6 +15,8 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
 
       - name: Install optipng
         run: |