Change wallpaper powershell

Question

Hello i'm trying to make a little script to change my wallpaper every given time i have a folder in which the pictures are name 1.bmp , 2.bmp etc

i made this script but it doesn't work at all

PS D:\Téléchargements\images\Wallpapers> for($i=1; $i -le 6; $i++){
>> reg add "HKEY_CURRENT_USER\Control Panel\Desktop" /v Wallpaper /t REG_SZ 
/d D:\Téléchargements\images\Wallpapers\$i.bmp /f
>> Start-Sleep -s 10
>> rundll32.exe user32.dll, UpdatePerUserSystemParameters
>> Start-Sleep -s 2
>> }

can someone explain why please :(

PS : the start-sleep values are totally random and here for testing

Answer 1

This should fix the problem(checked in win 10):

 reg add "HKEY_CURRENT_USER\Control Panel\Desktop" /v Wallpaper /t REG_SZ /d h:\Quotefancy-1542-3840x2160.jpg /f
 Start-Sleep -s 10
 rundll32.exe user32.dll, UpdatePerUserSystemParameters, 0, $false

or you can use win32 api like this:

$setwallpapersrc = @"
using System.Runtime.InteropServices;
public class wallpaper
{
 public const int SetDesktopWallpaper = 20;
 public const int UpdateIniFile = 0x01;
 public const int SendWinIniChange = 0x02;
 [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
  private static extern int SystemParametersInfo (int uAction, int uParam, string lpvParam, int fuWinIni);
 public static void SetWallpaper ( string path )
 {
  SystemParametersInfo( SetDesktopWallpaper, 0, path, UpdateIniFile | SendWinIniChange );
 }
}"@
Add-Type -TypeDefinition $setwallpapersrc

[wallpaper]::SetWallpaper("h:\Quotefancy-1542-3840x2160.jpg")