Ooooh! Mine is an example 
WOO! I'm pretty chuffed with that 
I might make a new one shortly
I think the size depends on the information you put in your badge (Posts, kudos, etc).
WOO! I'm pretty chuffed with that I might make a new one shortlyI think the size depends on the information you put in your badge (Posts, kudos, etc).
I just created some blanks to test it and without changing any other settings, I found that 146 X 195 fit perfectly - however - given that the "background" can be stretched, shrunk or just have part of it shown, if you just want it as "wallpaper", you can use almost any size you like.
Also, I can't say if it makes a difference to how they appear in the forum itself but the preset templates provided appear to have varying dimensions and even the small, inset avatars vary in size and shape - so it's not really possible to create full-blown template.
Regardless - here's a "blank" which may be useful (give me a minute or two after posting this so I can double check that it doesn't get scaled or other altered after posting)
Edit - just checked and right-clicking and using "save image as..." in Firefox downloaded a copy at the same dimensions as the original.
If someone wants to try that and let me know if it works and fits correctly - that would be useful.
(Now to try and get my animated Minky back :))
Okidoke....
Played around a bit and it seems that 146 width is a fraction too much - 145 seems to be right.
Height is not straight forward - about 193 works BUT only if you don't select any of the options to display "additional information" such as kudos, solutions etc - if you want to display any of those, the overall box height is increased but your backdrop image isn't stretched, it's tiled.
So - if you want a "wallpaper" effect where tiling is okay, don't worry too much about the sizes - but if you want to show a specific image in full, you'll need to make one that fits your personal settings - there's no "one size fits all" template.
And the other part that may confuse...
There are four basic templates on the forum - those determine the placement and format of your text but they also superimpose graphics over your image. Both "splat" and "moder tech" superimpose opaque graphics - and will hide your background image. "Tokyo Madness" superimposes transluscent, rectangular boxes where the text and avatar appear - which may or may not work with your backdrop image. "Bayfrog" has the least imagery - just the grey box with blue "hashing" on the centre section.
Also note - when you upload your backdrop, the "sample" you see on the screen is nothing like what you'll see on the forum itself - a correctly sized image will appear on there as too small and is repeated. Trick - have another tab open showing one of your posts. Upload your blackdrop then save your new image - go back to that other tab and refresh the page to see what your new badge actually looks like.
Hope that helps
Okay, here's mine I am by NO means, a very creative person 
It's VERY simplistic and it works. It DOES cut off a few pixels early bit I like it :).
Needs to have all the options checked but it works well with the text and the phones background which is o2's wallpaper that I photoshopped (with paint :smileytongue:) onto some high-res images of the Z10
A quick tip to you all, because the image doesn't stretch, sometimes you'll get another tile under or next to the picture. To avoid this, either stretch it yourself OR if you don't want to do that, add white space around your picture. It doesn't matter how many pixels that white space is because it just goes over :).
Meh - Mine is pretty boring but I quite like it
