Windows 7 Orb Wallpaper is of 2560 x 1600 resolution. You can edit and resize in Adobe Photoshop or similar programs (or use MS Paint if you do not have such programs installed). There is not much problem if you download and use it directly as wallpaper; but resizing according to your screen resolution is highly adviced .
This 3D rendered Microsoft Windows 7 wallpaper is designed by me. Finally, I decided to put in my own website for our visitors.