Abstract : With the ease of digital image manipulation, image forgery has become a common concern. The fast development of commercial image editing software's such as Adobe Photoshop dramatically increases the amount of doctored photographs circulated every day. First, various image forgery detection techniques are classified and then its generalized structure is developed. To restore the traditional trustworthiness on digital photos, image forensics analyses that can reliably tell the origin, integrity and authenticity of a given image are urgently needed. we propose several new image forensics tools. These forensics tools help expose common image forgeries, especially those easy-to-make forgeries, which can hardly be seen directly by human eyes.