Lossy vs Lossless Compression: What's the Difference?

Lossy vs Lossless Compression: What's the Difference? Pick up any JPEG, and you have already taken a side in the lossy vs lossless compression debate — probably without realizing it. Most developers understand the basic split ("JPEG = lossy, PNG = lossless") but stop there. That mental model breaks the moment you encounter WebP or AVIF, both of which support both modes. And it leaves you guessing on the question that actually matters: which type is right for this specific image? This article covers how each compression type works under the hood, shows real file size data across quality levels, and gives you a decision framework you can apply immediately. What Is Lossy Compression? Lossy compression permanently discards image data to achieve smaller file sizes. The discarded data is gone — you cannot recover original pixel values from a lossy-compressed file. What makes lossy compression smart (rather than just destructive) is which data it throws away: information the human visual syst