In this digital era, all kinds of media data are recorded and presented digitally. The popularity of digital devices also brings up the needs for new digital data applications, and digital forensics is one of them. This study is to analyze the relationship between digital cameras and images produced by them. Digital image processing technology is first applied in the identification procedures in order to get images' features. Those features are later trained and classified to identify the images' original sources by using SVM (support vector machine) techniques. In addition, the identification features are further analyzed for improvements for enhancing the precision rate of the identification. Since camera manufacturers have various designs of image formation processes for digital cameras, the distinctive digital image feature will be identified and analyzed. This research not only identifies the camera sources among different manufactures, but also those of the same manufacturer with similar models. Therefore, the potential limits of this identification method will be verified by the research results.