Update image auto compression

Author: 4ian

.github/workflows/calibreapp-image-actions.yml

@@ -43,6 +43,9 @@ jobs:
           githubToken: ${{ secrets.GITHUB_TOKEN }}
           # For non-Pull Requests, run in compressOnly mode and we'll PR after.
           compressOnly: ${{ github.event_name != 'pull_request' }}
+          # Avoid progressive degradation of quality
+          pngQuality: '100'
+          minPctChange: '15'
       - name: Create Pull Request
         # If it's not a Pull Request then commit any changes as a new PR.
         if: |