diff --git a/README.md b/README.md
index ec61e5b..cc816f8 100644
--- a/README.md
+++ b/README.md
@@ -55,7 +55,7 @@ Frontend:
 - `RpgRoller/Components/WorkspaceQueryService.cs`: browser-facing read client for workspace data
 - `RpgRoller/wwwroot/js/rpgroller-api.js`: browser interop for auth forms, session storage, SSE wiring, and DOM helpers
 - `RpgRoller/wwwroot/styles.css`: app styling, light and dark theme variables, and responsive layout
-- `RpgRoller/wwwroot/images/light.png` and `RpgRoller/wwwroot/images/dark.png`: themed workspace background art
+- `RpgRoller/wwwroot/images/light.webp` and `RpgRoller/wwwroot/images/dark.webp`: themed workspace background art
 
 Current repo note:
 
diff --git a/RpgRoller/wwwroot/images/dark.png b/RpgRoller/wwwroot/images/dark.png
deleted file mode 100644
index 3da2857..0000000
Binary files a/RpgRoller/wwwroot/images/dark.png and /dev/null differ
diff --git a/RpgRoller/wwwroot/images/dark.webp b/RpgRoller/wwwroot/images/dark.webp
new file mode 100644
index 0000000..55e6a33
Binary files /dev/null and b/RpgRoller/wwwroot/images/dark.webp differ
diff --git a/RpgRoller/wwwroot/images/light.png b/RpgRoller/wwwroot/images/light.png
deleted file mode 100644
index 4091cbe..0000000
Binary files a/RpgRoller/wwwroot/images/light.png and /dev/null differ
diff --git a/RpgRoller/wwwroot/images/light.webp b/RpgRoller/wwwroot/images/light.webp
new file mode 100644
index 0000000..7a96437
Binary files /dev/null and b/RpgRoller/wwwroot/images/light.webp differ
diff --git a/RpgRoller/wwwroot/styles.css b/RpgRoller/wwwroot/styles.css
index 08b2fd1..d12fabf 100644
--- a/RpgRoller/wwwroot/styles.css
+++ b/RpgRoller/wwwroot/styles.css
@@ -15,7 +15,7 @@
     --public: #2d6645;
     --private-self: #4f3a8f;
     --private-gm: #915119;
-    --page-background: url("/images/light.png");
+    --page-background: url("/images/light.webp");
     --card-strong: #fff8ea;
     --accent-dark: #2f4f34;
     --accent-2-hover: #6b2419;
@@ -95,7 +95,7 @@
     --public: #78d08f;
     --private-self: #b9a0ff;
     --private-gm: #f0b16c;
-    --page-background: url("/images/dark.png");
+    --page-background: url("/images/dark.webp");
     --card-strong: rgba(13, 24, 39, 0.96);
     --accent-dark: #2d638f;
     --accent-2-hover: #ffd085;