This interesting photo was taken sometime around the year 2000 in Manilla, Republic of the Philippines. According to The Ghost Research Society, two girlfriends were out for a walk one warm night. One of them entreated a passing stranger to photograph them using her cell phone's camera (hence the low-resolution picture). The result is shown here, with a transparent figure seeming to tug on the girl's arm with a firm if friendly grip.
Without further information on this photo, we have to admit that the ghost could have been added with image processing software. But if it's genuine and untouched, it certainly qualifies as one of the best ghost photos.