In the present era of Internet multimedia data especially Images and Videos are the most widely used digital format for data transmission. However due to their large data sizes and constraint of low bandwidth capacity of communication channel it is very difficult to transmit them at optimum speed maintaining the signal quality. Compression therefore, is a vital tool that not only reduces the data size thereby leading to faster data transmission but also protects it to some extent from transmission errors. A large variety of Image and Videos compression techniques are employed each having their own strengths and weaknesses. This paper is an effort to present an overview of image and video compression techniques, their working and comparison.