diff --git a/psalm.xml.dist b/psalm.xml.dist
index 1ca66e34..9cee6e9e 100644
--- a/psalm.xml.dist
+++ b/psalm.xml.dist
@@ -22,6 +22,12 @@
                 <referencedMethod name="PHPUnit\Framework\MockObject\Builder\InvocationMocker::with"/>
             </errorLevel>
         </InternalMethod>
+
+        <UndefinedClass>
+            <errorLevel type="suppress">
+                <referencedClass name="GdImage" />
+            </errorLevel>
+        </UndefinedClass>
     </issueHandlers>
     <plugins>
         <pluginClass class="Psalm\PhpUnitPlugin\Plugin"/>