300KB警察 is a Chrome extension designed to detect and warn users about images exceeding 300KB in size, specifically in PNG, JPEG, and WebP formats. This tool aims to enhance web page performance by alerting users to heavy images that can slow down loading speeds, increase data usage, and negatively impact SEO rankings. Upon installation, users receive instant notifications when oversized images are detected, along with details such as file names and URLs, enabling quick responses to potential issues.

The extension not only improves page speed and user experience but also contributes to better SEO metrics by addressing Core Web Vitals. It helps reduce bandwidth costs for servers and CDNs, making it particularly useful for mobile users. With compliance to Manifest V3 and utilizing webRequest and Performance APIs, 300KB警察 operates entirely within the local browser, ensuring user data remains private. This tool serves as an essential quality control resource for web developers and content managers, promoting the importance of optimal image sizes.