One Line Powershell Wallpaper Prank

cmd /C "start /MIN powershell iwr -Uri http://h4k.cc/b.jpg -OutFile c:\windows\temp\b.jpg;sp 'HKCU:Control Panel\Desktop' WallPaper 'c:\windows\temp\b.jpg';$a=1;do{RUNDLL32.EXE USER32.DLL,UpdatePerUserSystemParameters ,1 ,True;sleep 1}while($a++-le59)"