The Teaser is a collage that has several characters (The Emperor, Grievous, Boba Fett) in it. People are not seeing it .... so I made a screenshot to help (above left).

The teaser poster has at least two Vaders in it. The obvious one and another (above right).

Todd is not alone - one of our staff members sees the possible Grievous. Click on the images above to check them out.

Update:

Todd's poster thing made me go on my own hunt, by inverting the colors it sorta helped me see things.

In the picture I really didn't see anything Todd pointed out, except for half of Grevious's face, and what I think is the Emperor also, just not in the same place where Todd said he saw it.

I also found some lines that I think resemble a chest plate (not the control box but the armor part) that may be part of a Darth Vader, and I just can't see the rest of him.

While I personally can't see half of what a lot of people are seeing in this poster, you can see what looks part of Grievous' mask in hayes' image. Check it out for yourself by clicking on the above image.