fix: require client secrets and sanitize uploaded images

README.md

@@ -4,7 +4,7 @@ An asynchronous proxy for image generation through Google Gemini or OpenRouter.
 
 ## Start locally
 
-Requirements: Python 3.12 or newer.
+Requirements: Python 3.12 or newer. Uploaded images are decoded and re-encoded with Pillow; only JPEG, PNG, and WebP are accepted.
 
 ```sh
 python -m venv .venv
@@ -63,6 +63,7 @@ The built-in `nano-banana` alias defaults to Gemini 2.5 Flash Image. Set `GOOGLE
 | `DB_PATH` | `./data/proxy.db` | SQLite database location. |
 | `MAX_UPLOAD_BYTES` | `52428800` | Aggregate raw image upload limit. |
 | `MAX_IMAGES` | `8` | Maximum reference image count. |
+| `MAX_IMAGE_PIXELS` | `25000000` | Maximum width × height for each uploaded image. |
 | `HTTP_TIMEOUT_SECONDS` | `300` | Overall upstream request timeout. |
 | `CONNECT_TIMEOUT_SECONDS` | `15` | Upstream connect timeout. |
 | `GOOGLE_MODEL_NANO_BANANA` | `gemini-2.5-flash-image` | Native Google alias target. |