Oh, come on! It's just 10MB to download... Actually it can be pretty much understood by the previewif the wall is going to be crappy. Besides, I let you know about the files' resolution. I'm sorry, but I can't see a problem here. I download walls by Deviants myself from time to time, and if I realize that the files I've downloaded are not as good as I had believed them to be, I just delete them. Not a big deal at all.
What watermark are you talking about? There is none! There is only my logo and it doesn't ruin the picture at all. Moreover, you can't remove it. And a lot of people upload their walls the same way I do. I totally can't get you.
You're funny. Did you think a logo on a wallpaper wasn't a watermark???? Please tell me you are kidding. When you show me a respectable well known artist that sticks an obtrusive personal watermark of their logo or name on their work intended for users to display on their personal machines, then I may remotely make a small chance of recognition. And yes, I remove stuff I don't need or that hinders images all the time with the tools that people use every day like Photoshop, gimp and some of my homemade programs.
Seriously, I don't care what do you personally take as a watermark. You can read wiki to understand the difference between a watermark and a logo/sign. My logo is placed on the picture to protect it from stealing and using the wall somehow otherwise. And removing a sign is violation against author's rights. If you do it with other's walls, you better not to tell everyone about this. If you don't like the logo on my walls, fine! Go search for another walls. It's not a shop here, where you can demand anything of the Deviants.