diff --git a/aiui/packages/app/public/assets/img/bg-intro-3.webp b/aiui/packages/app/public/assets/img/bg-intro-3.webp
new file mode 100644
index 00000000..95738b54
Binary files /dev/null and b/aiui/packages/app/public/assets/img/bg-intro-3.webp differ
diff --git a/aiui/packages/app/src/pages/ChatPage.vue b/aiui/packages/app/src/pages/ChatPage.vue
index 83099016..e068f3d3 100644
--- a/aiui/packages/app/src/pages/ChatPage.vue
+++ b/aiui/packages/app/src/pages/ChatPage.vue
@@ -402,7 +402,9 @@ const { isDark } = useTheme()
 const isEmbedded = !!(window as unknown as Record<string, unknown>).__AIUI_EMBEDDED__
 
 // Background image URL — use BASE_URL for correct path in all deployments
-const bgImageUrl = `${import.meta.env.BASE_URL}assets/img/bg-intro-3.jpg`
+// 2912×1632 jpg was 1052K — visible as a slow paint over Tailscale/Tor.
+// The webp (1920w, q82) is 478K with no visible difference behind glass.
+const bgImageUrl = `${import.meta.env.BASE_URL}assets/img/bg-intro-3.webp`
 
 useAI()