This book is focused on resizing of image by arbitrary ration using DCT Technique.As advances in digital signal processing and digital media, many video streams and images are now transmitted and stored in compressed format. Accordingly, image manipulation in a compressed domain is usually more efficient than that in a spatial domain in terms of computational complexity and image quality.Among the many image manipulation processes, image resizing is a fundamental and important operation for various multimedia applications. Image resizing changes the size of image-the number of pixels used to represent the image to an arbitrary target size.Discrete cosine transform (DCT) is used for implementation. In this method a combination of forward DCT & IDCT will be used for the purpose of achieving arbitrary ratio image resizing.