You know, I know that the color can be quite annoying when you have a nice looking background and then your icon's mess it up. So I had this problem a long time ago. and Yes all of the solutions they gave work, but sometimes its the simplest one that slips our mind, Find where you got your wallpaper, see if the image is a .jpg file or a .bmp if its a jpg, open it up in Photoshop or ms paint and do "Save As..."; Save it as a 24-bit .bmp file. and make the new .bmp your desktop wallpaper.
