This book is about digital imaging. In particular the authors describe image acquisition, compression, transmission, storage, etc. With exception of a handful of very technical people, just about everyone else has no knowledge of this. The book is written for the general public, particularly for these who use smart phones to take, send, and receive pictures.Digital imaging is ubiquitous in our daily life.   We will start with camera capture, and go into details to describe every component from a captured digital image to its compressed version in term of a binary bit-stream, and to decoding the binary representation to recover the image. The mathematics of discrete cosine transform and entropy coding are discussed with illustrations. Industry standards including JPEG, JPEG 2000, and MPEG video are also introduced.