how to check if a photo is fake?

Most of the time it is quite easy to tell if a photo has been manipulated in Photoshop because a majority of people use the software clumsily leaving behind tell tale mistakes. To detect the mistakes of a well trained Photoshop artist you do have to have a relatively decent understanding of photography. Although that said, most mistakes that are made are quite obvious even to an untrained eye.

Now on the other hand if this digital image was created by a Canon 1DS you can in fact check to see if the image is valid because each image includes a unique digital signature which is broken if modified in Photoshop or any photo editing software.

Below is a link regarding the issue of forgery in digital photography.

It takes a good trained eye to detect some fakes, but many can easilty be noted just by a simple visual inspection. You can see if two images are combined into one by looking for any contrast.

Say there is a nice woodsy background with a person who might have been but from another photo and place into that one. The cut job on the person will look choppy and you might be able to see remnants from the background of the original photo it was in.

The lighting usually gets overlooked as well. There is most always a distinct light source and if one images has the left side of objects lit and the other image show the right side lit...you know both elements were not in the same shot at the same time.

Finally, look at the colors. Some images are bright and vibrant like professional photos... while others appear more muted or grainy...as in older photos from the 80s. These two types combined leave an obvious insdication the dont go together.

Hope these tips get you started!

Yes you can see signs in some but for example if I did some good editing and ran the photo through a filter or grain than it makes it more difficult to find. Adding items is more noticeable if they don't make a total change at the end, like changing it to black and white,grain,filter,contrast,saturation,etc. If you using to images there is always a difference in lighting,contrast,color,etc.

As far as a service there is not but if you have a photo in question post it here or a photog or photoshop message board. I am sure many people will give you 2 cents and than some.

Some people get sloppy with photo-editing. Just look really closely, your bound to find mistakes in their handy work.

well, my friend found this girls picture on a dating site, saved it, took it to his photoshop and messed with it somehow. (i dont know how it works cuz i dont have photoshop). by lightening the pic a lot i guess, he could tell that the girl blacked out parts of her body to make her about 50lbs thinner...

well if an item was removed from the photo (from photoworkshop or something similiar) there will be a horizontal line [hard to see but if you look close enough]

If the retoucher is good you won't be able to spot it!