I love the differing expressions. It reminds me a lot of what Leonardo da Vinci did in The Last Supper with the Apostles. You could almost even go into a fake The Last Supper-style analysis with this pic.
 
You have Twilight and Applejack, bowing in loyalty, dedicated to their princess, totally unbeknownst to them that ponies behind them aren’t doing the same.
 
The main differing expression is Rainbow Dash. Some might say she’s scowling at Pinkie for being a loony, but to me, perhaps her scowl is directed at somepony else since it also looks like she isn’t even acknowledging Pinkie and looking past her. Maybe it’s directed at Twilight and/or Princess Celestia. She looks at the latter two with contempt, perhaps emanating some form of betrayal, ironic given her element. That pinkish effect on her form gives her a sort of symbolic appearance in a manner similar to how da Vinci portrayed Judas cast in shadow.
 
You have Fluttershy making a worried expression, apparently directed at Rainbow. Perhaps she sees Rainbows expression and is either concerned or knows what Rainbow is thinking and looks back on instinct.
 
Pinkie also sees Rainbow’s scowl and tries to cheer her up despite not knowing what its about, which in turn causes Rarity, previous ignorant of the situation to look back at Pinkie in annoyance.
 
Princess Celestia, in the meantime, is blissfully unaware.
 
 
Damn, I have too much time on my hands.

@Lucky Shot  
@Dragonmage  
I’m inclined to think you’re both correct.

The days when the mane 6 were the go to heroes of Equestria.

Pity this was so under-seen back in the day.

The good ole days…

Aww… Look at that… One of my favorite pics of all time is being featured. Yay!

Royal hoof kiss.  
Pinkie is just leaving after she already took a lick.

@Officer Hot-Pants  
Pinks.

@Officer Hot-Pants
 
The screen scroll

Wow? What’s up Dash’s butt?

This makes me feel sad…

Our heroes. May they be remembered through the ages.

Wow, I had missed this entirely until now.

Daww, it looks like Applejack and Twilight are getting married!

This gives me nastalgua in a good way

This is one of my favorite images to have ever came out of the fandom. I actually got it printed out as a 36” x 18” poster (with CuteSkitty’s permission, of course) and had it hanging over my desk for years.
 
My current apartment isn’t too fond of people doing that, so it’s not up now. But once I move, I’m gonna do that again.

@pwingbrony  
Pinkie.

What’s up with the four in the back?

Lovely! ❤

welcome back unicorn Twilight,my old friend,long time no see.

Old, but still pretty art.

What a gorgeous piece!

@poiuj1  
Pinkie, Pinkie, Pinkie

Oh Pinkie. :3