Web image compression is the single most impactful optimization for page load speed. Images account for 45-70% of page weight on most websites, and proper compression can reduce this by 60-80% without visible quality loss.
For web optimization, follow these target file sizes: hero images under 200KB, content images under 100KB, thumbnails under 30KB, and icons under 10KB. These targets assume images are served at their display dimensions.
ImgTools provides free browser-based compression with a quality slider. Upload your image, adjust quality to meet your target file size, and download. For web images, JPEG at 75-85% quality provides the best balance. For images that need transparency, use WebP or PNG.
Beyond compression, consider these web optimization practices: serve images at exact display dimensions, use responsive images with srcset, implement lazy loading for below-the-fold images, and use modern formats like WebP for 25-35% additional savings over JPEG.
All processing happens locally in your browser. Your website images stay on your device throughout the optimization process.