I can't remember which threads it was. Each different domain is remembered by Firefox after I've denied it the first time.
The current list of domains is:

i11.photobucket.com
i12.photobucket.com
i13.photobucket.com
i176.photobucket.com
i193.photobucket.com
i23.photobucket.com
i3.photobucket.com
i325.photobucket.com
i35.photobucket.com
i36.photobucket.com
i41.photobucket.com
i59.photobucket.com
i785.photobucket.com
i82.photobucket.com
i948.photobucket.com

Just checked THIS THREAD and it tried to set another.
I viewed the location of everybody's avatar and I there are several avatars listed as on i(number).photobucket.com
They are:
JJW009
Adidan
Linuxuser
Based on the last cookie it tried to set, I think it may be Adidan's avatar, but I'm not sure.

Edit

I think it's davrosG5's avatar.

It could of coarse be Photobucket just being bastards.

An image can't set a cookie. It's only if someone has put excess code in somewhere, for example ?action=view&current=avatar.jpg instead of just avatar.jpg

Well whatever it is, Photobucket is still trying to set cookies on my pc when I'm browsing these forums. I'm assuming it's the avatars as they're the only thing on those threads that are hosted on photobucket.

There's an option to turn off the display of avatars
[ User Control Panel > Board Preferences tab > Edit display options ]



Not sure if that still downloads the images, though?
Worth a try?

Or, if your router (or browser) allows you to block domains or cookies, try adding "photobucket" to the blacklist? If nothing else, that should help to identify the culprit - the one with a missing graphic as their avatar!

My avatar is definitely hosted on Photobucket but I wasn't aware that it was a problem for anyone.
As far as I can tell it's a direct link to the picture (a .png) in one of my Photobucket albums.

This is the link I used to load it into the forums: http://i270.photobucket.com/albums/jj82/davrosG5/Avatars/Avatar2.png

I'm not turning off avatars, I like them. It won't take too long before all the i domains Photobucket uses will be remembered by my browser, so it's only a short term issue.
I guess I'm just ranting/venting at the fact Photobucket wants to set a cookie for no reason in the first place.

I think it's the first time I see everybody's avatar that's hosted on Photobucket, not just yours.
This is clearly a photobucket issue, not anything wrong with any individual avatar on this forum.
Strangely it's only the ixx.photobucket domains that are doing it.The img.photobucket domains don't try to set one.

I've had a look and I can't find any settings in Photobucket to account for it trying to set cookies.
That's just odd.

Probably them doing for advertising revenue. Cheeky buggers!

I've changed my avatar to img.photobucket from i23.photobucket

Let's see if that changes anything.

I won't know. Firefox has remembered to block that domain now.

I wonder if the cookie is part of Photobucket trying to track the number of times the image is viewed by a unique visitor.

The Northern Line was suspended because of a van full of tyres was on fire on the A406 as the van was parked up under the bridge with the tracks on it. However no-one relayed that to us commuters. All we were told was that the line was suspended because a car was on fire. Which sounds bloody ridiculous.

So after waiting around Golders Green which was now a car park, I had a nice 3 mile walk to where I could get a bus home. At least it wasn't raining.

My front tyres were wearing out so I went down to Kwik-Fit to ask about getting some replacements. The chap there recogised me as he's done tyres on my car, and my sister's car, quite a few times. He could order the replacements and said he'd give me 20% off. "Sweet" I thought - that's pretty much the same as ordering the tyres online and getting them to fit it. I asked him to go ahead and order them, and we planned to fit them this morning.

The chap hasn't turned up to work today. There are other cars being serviced which will go first. I saw one guy reverse a Micra into a plant pot. The main chap there asked if I'd leave my car there. No frikkin' way! Anyway, the questions now become: will they fit the tyres today, and will they still honor the 20% discount? If they can't, I haven't paid anything and hence haven't lost out. But it's just a complete PITA.