I like LOST, too, and am gearing up for the final season, so I'll play along.
To start off, let's look at both promo shots:
photos: slashfilm. Click to see a larger version.
Next, let's orient ourselves with a photo of Da Vinci's original, and a who's who (via Art History.about.com):
- "Bartholomew, James Minor and Andrew form a group of three. All are aghast, Andrew to the point of holding his hands up in a "stop!" gesture.
- Judas, Peter and John form the next group of three. Judas, you will note, has his face in shadow and is clutching a small bag (of silver?). Peter is visibly angry and a feminine-looking John seems about to swoon. Note that in Dan Brown's The Da Vinci Code, it is offered that John is in fact Mary Magdalen, pregnant with Jesus' child.
- Christ is the calm in the midst of the storm.
- Thomas, James Major and Philip are next. Thomas is clearly agitated, James Major stunned and Philip seems to be seeking clarification.
- Matthew, Thaddeus and Simon comprise the last group of three figures. It appears that, when a situation turns ugly, Simon is the "go to" guy for explanations."
Okay, let's see what we've got here. We'll start with similarities.
In both photos, John Locke is in the "Christ" position in the center of the table. Ah, but which Locke is he? We know that "Locke's" body fell out of the casket at about the same time that "Locke" and Ben were in with Jacob. Sayid is in the "Judas" position. Kate is in the "John/Mary Magdalen" position (assumed because she is sitting down). Sawyer is in Peter's position, possibly of denial, or most favored.
In both photos, the "group of three" on Locke's left hand is a group of four. There's one too many there. Was it deliberate? Frank Lapidus and Ilana are minor characters, in the positions of the minor apostles. Jack is on Locke's left, in the position of Thomas, the doubter. This fits, and Jack has been compared to Thomas in the series before.
Both photos show the characters' shirt colors clearly, and the show has used the "red shirt" gimmick before. Note that Richard's shirt is red. Ilana's red shirt is covered by a vest. Also note that all the other characters have solid shirts except for Sawyer's multi-colored and Ben's stripes. Can leopard Ben change his stripes? Is Sawyer's plaid reminiscent of Joseph's coat of many colors? In neither photo is the color of Claire's shirt clear.
I've mentioned the significance of shoes on LOST before. The most notable pair is the white tennis shoes that Jack got to bury his father in. Note that only two of the characters' shoes are showing: Ilana and Lapidus. Also note that many of the characters' legs are not visible, in spite of the fact that they certainly could be. Missing legs: Hurley, Claire, Richard, Miles, Sawyer, Jack and Ben.
Note Sawyer's position in both photos. In both cases, leaning casually, perhaps protectively on Kate's chair. It's casual, but possibly significant. Also note the skull at Sayid's feet.
That brings us to the differences. Most notably, three of the characters change location. Is there significance to Jin's being with Sun in one photo and apart from her in the other? What about Miles and Claire switching sides? Anyone notice that the "cross" over Jack's shoulder in one photo is obscured by him in the other?
I'm sure these ideas have been mentioned by dozens of other people, just as I'm sure I've missed some key elements. Even so, that's a lot to think about in the next four weeks before the final episode premieres.