I did an image search for pictures of Bill Hicks, and here is some of what I've found.
Notice how very non-similar they are. Notice the differing forehead lines, eyebrows, eyes, EARS, nose, mouth and chin. Alex has a MUCH larger neck. Bill's lower lip is angled outward toward the right, Alex's is not.
Something else I found says it's from Mark's site. This proves to me without a doubt they are NOT the same person. The teeth are SO DIFFERENT. Bill's upper right teeth curve inward towards his tongue, and upper left teeth angle outward towards his cheek, and the arch is wider. Alex's upper teeth are more straight, with quite a narrow arch. Also notice the different lower teeth on both men. Once again, different foreheads, eyebrows, eyes, etc. Notice how the dimples on the left side of their faces are in different places, and their overall face shapes are different. The left eye on Bill is larger, while the opposite is true for Alex. They have different lines around their eyes. Bill's eyes are larger anyway, and a longer chin.
Notice the difference in the width across his eyes.
This is why it's so important to show the full face
of both people being compared.