Computer Science for IGCSE & O level - Data Representation (Section 12 - No. 34)
What is the main difference between lossy and lossless compression?
Lossy compression reduces file size by discarding data; lossless compression does not.
Lossy compression results in better image quality; lossless does not.
Lossy compression is faster than lossless compression.
Lossless compression can only be used on images.
Maelezo
The key difference is that lossy compression can remove data, while lossless doesn't.