Posted 19 April 2012 - 10:31 AM
Change resolution, or size can mean the wallpaper isn't sized for your screen size, i.e.; 1024x768, etc. Windows allows you to better fit wallpapers by using Center, or Stretch (it defaults to stretch usually which is sometimes wrong). Although I don't know why Windows would change the resolution upon boot, it shouldn't be doing that.
Sometimes if the size is really off such as too big of a wallpaper I usually resize the image down in a painting program such as Paint.Net. Or just look on the site the wallpaper came from for a more correct size for what you have your monitor resolution sized at.