Using a CDN is critical for fast and reliable delivery of media files like images and audio. CDNs reduce latency, lower bandwidth costs, improve scalability, and enhance security. For image delivery, best practices include selecting efficient formats (e.g., WebP, AVIF), implementing responsive images with srcset, using lazy loading, and leveraging CDN optimization features like resizing and compression. For audio, efficient codecs (e.g., AAC, Opus), adaptive bitrate streaming (e.g., HLS), HTTP range requests, and effective caching with proper Cache-Control headers are recommended. Advanced strategies like using a multi-CDN setup, edge caching with cache invalidation, token authentication, and real user monitoring help maximize performance and security. These techniques improve user experience and reduce server load.