The aim of every digital system designer is to create a system that will be economically viable for users, capable of storing large volume files whether image, audio, visual and textual signals and make it easier to transmit across different platforms. The characters of digital representation are presented as picture elements (pixels) most time presented in bits per pixel (bpp) or raster. To achieve this, compression techniques which may be lossy, or lossless is adopted. This paper x-rays the application of one of technique called Discrete Cosine Transform (DCT) in compression of image for the same purpose. The experiment was conducted using Matrix Laboratory (MATLAB R2007b). The experiment showed interesting characteristics of original and compressed images signifying that DCT is useful in compression of image, audio and visual files.