JPEG
Compression
JPEG is classified by two different methods of compression:The first method is based on DCT (Discrete Cosine Transformation), while the second is based on Independent Function (Spatial) utilizing DPCM (Differentiated Pulse Code Modulation).
The compression ratio of DCT is large, but picture quality is poor. (Non-lossless coding).
In Spacial, the compression ratio is small, but there is no loss in quality. (Lossless coding).