Digital images play an important role in many application areas. Because of the easy availability of photo editing software and tools, it becomes problematic to use the digital images in applications where their genuineness is of prime importance. Therefore, it is necessary to create forensic techniques which are capable of detecting the tampering in image. Most common operations that are involved in the creation of forged images are contrast enhancement, copy-paste forgery etc. In this paper, the authors present different techniques for detecting global contrast enhancement and copy-paste forgery.