A word of caution: image analysis is quite complex, and I have seen people embarrass themselves by reading too much into the results. Do not expect this to tell you definitively whether a photo is "fake". The creator of FotoForensics warns: 'Any single analysis algorithm can generate noise that may result in a false-positive interpretation. You should confirm your results with other analysis methods. ("Observation" is always a good one, so is "common sense".)'
Tools for digital picture analysis, including error level analysis, metadata, and tutorials.
Digital image forensic analyser