This document provides a review of techniques for detecting image forgeries in image processing. It begins with an introduction to digital images and image processing. It then reviews several papers that have proposed various techniques for image forgery detection including pixel-based detection, key point-based detection, and detection of copy-move forgeries. The document also describes challenges in digital image processing and different categories of image forgery detection techniques. It concludes that accurate methods are needed to detect image forgeries using image processing approaches and reviews can help improve existing techniques.