I think this site needs a Halo 3 screenshot forum.
Pros:
Screenshots won't dissapear into later pages after a few minutes.
Better responses because we're smarter than Bungie forums.
Better screenshots because content on this site is usually best (tricking/glitches/montages). I think screenshots will do the same.
Less spam because with a smaller community and screenshots not being pushed to later pages, there won't be the urge to bump threads.
Perhaps a different section (not forum) for individuals' galleries and allowance of comments to individual pictures? That'll take away the need to post every time you get a new screenshot and allow ratings (which will also promote the downloading of good videos).
Cons:
Links will usually be to Bungie's site and individuals' albums.
There can still be spam, but much less. I'd guess it might be about as active as Yap and Blabber.
Any other Pros/Cons? I'm pretty sure there is some I didn't come up with.
I think that a forum like this can include videos as well. I never download videos from Bungie because they never have good descriptions ("DOWNLOAD THIS!" does not allow a quick preview of what a video contains) and of course, there's too many postings and thus a higher chance of very lame videos. Better descriptions with a better community can save time because of the need to download videos (before Bungie's new video to computer thing).
And with that, here's a few of my favorite screenshots with descriptions (hosted on my site rather than Bungie's).
My other screenshots are located here on my site:
http://bierwiser.uberlisted.net/Halo/
Screenshots.
This is my favorite screenshot, though it wasn't taken by me. I am driving the Hornet, though. I forgot what other spots were occupied by which players. I forgot who else was in this game besides retardedpenguin (game details are purged). 
Below this link is just another view, by me.
Epic Screenshot
Warthog Hornet Attack
My almost overkill with a Spartan laser. If only just a second earlier.
Almost
One of my other favorites. Just me being hardcore, fighting on top of some fusion cores.
Being Hardcore
Me and a friend in double team. I didn't get the kill with the Spartan Laser, my friend's Sniper Shot shot got him first.
Criss Cross
Weird screenshot from lag.
Dead Overshield
Best AI character ever. Shot me out of the air with a Fuel Rod Cannon.
Fuel Rod Midair
Immature screenshot.
Happy Time
My friend Jeremy got stuck twice with a Ghost and then a Chopper while playing campaign. Here are the two screenshots showing it.
Jeremy Stuck 1
Jeremy Stuck 2
For anyone who likes Security armor, here's a spruced up version of my old player model through Photoshop.
Background
Added a few minutes later...
The only human player is one of these hornets (me). The rest are AI, and apparently they all suck at flying (including a Pelican driver).
Dog Fight Pile
This screenshot is boring. It's only funny to me. I almost got run over by some teammates so I sent them on their way.
Hammer Baseball
Look at the bullet line from the Sniper Rifle. Magic bullet?
Impossible Betrayal
A true spawn killer. I was killed by the Jackal before I hit the ground after spawning.
Spawn Sniped
Enjoy.