diff --git a/.woodpecker/test.yml b/.woodpecker/test.yml
index 2a68c76..9f43757 100644
--- a/.woodpecker/test.yml
+++ b/.woodpecker/test.yml
@@ -9,7 +9,7 @@ steps:
       WP_TESTS_PHPUNIT_POLYFILLS_PATH: vendor/yoast/phpunit-polyfills
     commands:
       - apt -y update
-      - apt -y install libonig-dev libicu-dev zlib1g zlib1g-dev
+      - apt -y install libonig-dev libicu-dev zlib1g zlib1g-dev libpng-dev
       - docker-php-ext-install mbstring mysqli pdo_mysql intl gd zip bz2
       - docker-php-ext-enable mbstring mysqli pdo_mysql intl gd zip bz2
       - composer require --dev yoast/phpunit-polyfills:"^3.0"