优化rmbg服务的保存图片逻辑，提高效率

apps/rmbg/service.py

@@ -368,7 +368,8 @@ class RmbgService:
         """保存图片到文件并返回URL"""
         filename = f"rmbg_{uuid.uuid4().hex[:10]}.png"
         file_path = os.path.join(self.save_dir, filename)
-        image.save(file_path, format="PNG")
+
+        image.save(file_path, format="PNG", optimize=False, compress_level=1)
         image_url = f"{self.download_url}/{filename}"
         return image_url