What Is Lossless Compression?

Lossless compression means that no information is lost during the compression process. If you compress something using lossless compression and then decompress or expand it back, you get something identical to the original byte for byte, bit for bit,. That's what lossless compression means. Lossy compression means that you're actually willing to lose some information during the compressed process. And so why would you even use lossy compression? Because when you're willing to losing some information, you can generally achieve much greater compression ratios.