how do you make it span like that?

I run dual 1600x1200 (3200x1200 total desktop space) and getting a wall paper to span both monitors depends on your setup. I use a program called Ultramon to manage my desktop, including the background. Sometimes you have to split the image in half, other times you can adjust the settings until you find one that works. I believe "tile" is a good place to start with a Windows box.

I have 3 computers with pretty funky resolutions so the wallpapers I use are very custom. I've kept them backed up and can't say I will be changing any time soon. Photoshop has been a great aid in my quest for custom desktops. I've even gone so far as to piece together characters which are panned across in the credits to assemble the entire character.

While we're on wallpapers though, anyone use anime wall paper on devices besides their computer? Say PDA (Azumanga Daioh), cell phone (Ah! My Goddess), ect...

if i could, i soooo would -.-

i haven't figured out a way to do that yet with my phone. i could prolly ask at a V place, but that would mean expending extra effort at the moment :P

have you tried animepaper.net?
they are the only wallpaper site i can think of at the moment which i know and use that has some insanely huge resolution wallpapers.

nope {huggles her yuuko-san}

yes, my laptop named herself within 30 minutes of ownership. on the way home with me in the car actually. but yuuko-san is a worthy replacement to az-chan who has been redubbed j-chan is being cleaned up for my my girlfriend.
wow, off topic much -.-

anyhoo, no. i never experienced any slowing down in either computer, and especially not yuuko-san. she is one bad-ass momma az-chan was slow in her latter years, but that's cause i abused the heck out of her and she was 5 years old.

how do save your wallpaper files and how do you use them? out of curiosity...

I've had good luck with DisplayFusion for handling dual monitor wallpapers.

AnimePaper has that "get 'papers' to download!" thing going on though, which means I generally don't go there. I mostly go to moe.imouto.org for my high res needs, since that's precisely what it specializes in. They have people who do good scan cleanup there too. Some fanart can be huge and thus suited for walls, and for that I use danbooru.

I'll probably keep my current wallpaper for a long time, since it just works so damn well. I almost switched to a nice Miku wall recently, but 1) it was a bit small so the stretching was a tad too noticeable for me and 2) it was too briiiight. I like my wallpapers to be largely dark in color since I never turn my lights on and bright walls hurt my eyes.

a nice friend is letting me mooch off their account, but since i have my own scanner now i can actually get my own account started. thx for the additional website. i'll definitely be checking it out

I use M.I.org for a lot of my avatars. but you have to be very careful with that one because it is about 40% hentai.

You can blacklist 'rating:e' in your settings to block all explicit images. Generally they're pretty good about rating images explicit if they are, though perhaps not as thorough as danbooru currently is.