When redesigning an old website, image compression is a key step to boost loading speed and enhance user experience. Oversized images not only slow down page load times but can also negatively impact search engine rankings. The core principle is to minimize file size while maintaining acceptable visual quality. This can be achieved through format selection, compression tools, batch processing, and CDN integration.
Choosing the Right Image Format
Different formats suit different scenarios. JPEG is ideal for photos and gradient images, offering high compression but with some detail loss. PNG supports transparency, making it suitable for icons and screenshots, though files are larger. WebP, developed by Google, provides 25%-35% smaller file sizes than JPEG at equivalent quality, but compatibility should be considered. SVG is perfect for vector graphics and logos, scaling without distortion and keeping files small. For a redesign, we recommend: use JPEG or WebP for standard photos and product images; SVG or PNG for icons and logos; and PNG or WebP for images requiring transparency.
Recommended Online and Local Compression Tools
There are many compression tools available, depending on your usage frequency and preferences. Online tools like TinyPNG and Squoosh allow you to upload images for quick compression, ideal for small batches. Desktop software such as Photoshop's "Save for Web" feature offers fine-grained control over compression quality. Open-source tools like ImageMagick are great for developers to script batch processing. When compressing, adjust quality parameters: for JPEG, a setting between 75%-85% usually yields imperceptible differences; for PNG, reduce color depth or use lossy compression.
Batch Processing and Automation
Old websites often have hundreds or thousands of images, making manual processing impractical. Use batch processing tools like ImageOptim or RIOT to drag in multiple images at once, or write scripts using libraries like Sharp or Pillow for automated compression. For WordPress sites, plugins like Smush or ShortPixel can auto-compress uploaded images, but existing images from the redesign need manual import. Establish a unified standard: for example, limit all product images to a width of 1200px, set JPEG quality to 80%, and save as WebP format (keeping originals).
Using CDN and Image Acceleration Services
A CDN caches images on nodes closer to users, reducing load latency. Some CDN providers also offer automatic image compression and format conversion, such as Alibaba Cloud CDN's image processing or Qiniu Cloud's image handling. During the redesign, consider hosting images on object storage with CDN enabled, combined with automatic compression strategies, to further optimize loading speed. Note: evaluate costs and security before using external services.
Verification and Adjustment After Compression
After compression, verify the results. Use tools like PageSpeed Insights or GTmetrix to test page loading performance, especially focusing on "image optimization" recommendations. If quality drops noticeably, increase the quality parameter slightly. If some images remain too large, consider cropping unnecessary areas or switching to a more efficient format. After the redesign goes live, continue monitoring, as new content may introduce large images.
Conclusion
Image compression during an old website redesign is not complicated—the key is to establish a standardized workflow: choose the right format, use reliable compression tools, automate batch processing, and leverage CDN acceleration. This effectively reduces server bandwidth pressure, improves user access speed, and positively impacts SEO. After the redesign, incorporate image optimization into your regular maintenance routine to keep the website lightweight and efficient.
