When someone clicks on your Avatar, they get your User Card, which shows things about you. Join date, optional location, yada. This card can have a background image. Click my avatar, wait a sec for it to load and there’s a dude with glowing eyes assaulting you with a… wait for it… squeegee!
Obviously User Card backgrounds are tremendously useful! Everyone should want one! Well, what are you waiting for? 
My avatar is all-encompassing. It needs no background.
(Actually, I’m much too busy and important to deal with such trifles.)
All my first picks in my photo list got me told they are to large files and I would have to resize. So I’m gonna stick to my lazy guns and never do it.
I’ve loaded everything I think. Let’s see what my card background is.
Of course, that makes sense.
So what Anduin Exit are you?
My location says “Central Jersey and closer to Bree”, the background does indeed show Bree (and more) that Frodo passed through.
The one nearest the Bay of Belfalas 
I didn’t know I could add pictures there and to my biography. Thanks!
Frankly, I’m not too fond of my avatar. But it was the first image that was the right size and format.
Perhaps a picture of an inanimate carbon rod?
I’ve changed my avatar to the symbol of the Sons Of Ether (a fictional group of weird Scientists). I already like it a lot more than my old picture of Philipe LeMerchand (inventor of the puzzle box from Hellraiser). I’d like to use a picture of the back of my double breasted Victorian laboratory smock. But, I don’t know how to resize the image.
There’s others. Google “avatar resize”.
Thanks! My Google fu is surpisingly weak.
No problem! But that looks more like a magician’s smock. Lol.
The smock is covered in alchemical symbols. The SOE insist that what they do is simply advanced Science (always with the capital S). The 8 other Traditions insist it’s Magic. Either way, there are goggles, rayguns, scanners, etc
Wow. I wrote and deleted that it looked like an Alchemist’s smock because I thought that was too obscure.
Good choice. I hear the traffic near Forochel exit is a bitch
Some user card background info is handy. It’s nice to be able to see poster info at a glance. It is NOT nice when someone has blocked anyone from seeing their card info.
How is this allowed, anyway?
Do we really want any random schlub who joined yesterday to be able to hide their user info from everyone else? I don’t really think anyone should be able to do that, but if someone was allowed to do it I think it should be someone who is at least somewhat known and vetted.
The only thing the backgrounds do IMO is make the rest of the words hard to see. A decorative user icon is fine. But deliberately putting a busy background behind stuff that’s supposed to be legible is not progress.
And stay the hell off my lawn ya damn kids! And take yer talkin’ dog with ya’s!
Recovering from yesterday still. Let’s see.
Mine’s a hard-working beetle who has fallen off his turd ball. It makes me laugh. 
I haven’t been so excited for a feature since MySpace. 