diff --git a/src/public/invalid-content.png b/src/public/invalid-content.png
new file mode 100644
index 0000000..202d1ee
Binary files /dev/null and b/src/public/invalid-content.png differ
diff --git a/src/views/form.ejs b/src/views/form.ejs
index a0fa635..31facb7 100644
--- a/src/views/form.ejs
+++ b/src/views/form.ejs
@@ -105,7 +105,7 @@ function updateQR (e) {
         ["issuer_address", val("issuer-address")],
         ["issuer_city", val("issuer-city")],
     ].map(v => `${v[0]}=${v[1]}`).join("&")
-    qrcode.style.setProperty('background-image', `url("/api/qrcode?${qstring}")`)
+    qrcode.style.setProperty('background-image', `url("/api/qrcode?${qstring}"), url("/public/invalid-content.png")`)
 }
 btn.addEventListener("click", updateQR)