How Image Compression Works
Image compression reduces the file size of a digital image by removing redundant pixel data and optimizing how visual information is stored. There are two fundamental approaches: lossy compression (used by JPG and lossy WebP) selectively discards image data that the human visual system is least likely to notice — subtle color variations, high-frequency noise, and fine details in complex areas. Lossless compression (used by PNG and lossless WebP) rearranges data more efficiently without removing any pixels, producing smaller files with perfect quality.
ImgNeo uses format-specific algorithms tuned for each image type. For photographs, it applies optimized DCT quantization similar to JPEG but with modern psychovisual tuning. For screenshots and graphics with solid colors, it uses palette-based optimization to maximize savings while keeping text and edges sharp.
Lossy vs Lossless: Which Should You Choose?
Lossy compression is ideal for photographs, web images, and any scenario where file size matters more than absolute pixel perfection. At 75-85% quality, most people cannot tell the difference between a lossy compressed image and the original. The savings are dramatic — often 60-80% smaller.
Lossless compression is better for screenshots with text, logos, icons, medical images, and any image you might need to edit or re-save later. PNG and lossless WebP preserve every pixel exactly. The tradeoff is smaller file savings — typically 10-40%.
Best Practices for Optimal Results
Start with the highest quality source you have — compressing an already-compressed image compounds quality loss. Use the side-by-side preview to visually compare at 100% zoom; if you cannot see a difference, you have found your sweet spot. For website images, aim for under 100KB for most content images and under 200KB for hero images.
When converting formats, WebP almost always beats JPG and PNG for web use — it offers both lossy and lossless modes plus transparency support, and browser support is now over 95% globally. PNG remains best for graphics requiring perfect edges and transparency in legacy browsers.