I'm trying out SLUP, which lets you upload 20 textures a month for free. I hadn't really known what I was going to use it for, and I'm still not sure how much I shall, but I figured it was a neat thing to have, just in case, someday. Maybe pictures of my cats when I'm feeling cheap.
I might use it when the Beta Grid's being a pissy beast. Like, oh, now. Eventually I plan to have real avatars exported so I don't need to do as much testing on things with the less-than-accurate models they provide for us.
Note: it's in Japanese, so my very broken and out of practice kana tells me that キャンセル means "Cancel" and アップロード means "Upload". Aside from that...just guess a lot, like I do, I suppose. Currently there is no tga or png support, although it appears planned (I tried a bmp however, and it appeared to work- but there are no options in the SLUP like upload lossless and such). When you upload, the creator will be slup Reiko, not you- they do not ask for your SL account info beyond your username. As such, I wouldn't really recommend it for anything you want to have your name as creator on, obviously- which is why I shan't be using it for real versions, but I might use it to, say, compare SLuploader and regularly uploaded versions of sculpties. (As an aside, I uploaded a couple of small textures that needed pixel perfect reproductions, and while it may be on SL's part when you see it, even with SLuploader, they are not pixel perfect, and the seams are quite obvious. Means that I will have to unnecessarily use larger textures for some things, which it somewhat irksome. I'm trying to reduce the load on your system here, and you just tell me no.)