VB .NET - Trocar Papel de Parede do Windows

Public Class Form1

    Private Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Integer, ByVal uParam As Integer, ByVal lpvParam As String, ByVal fuWinIni As Integer) As Integer

    Private Const SPI_SETDESKWALLPAPER = 20

    Private Const SPIF_UPDATEINIFILE = &H1

    Private Sub SetWallpaper(ByVal imagePath As String)

        ' Verifica se o ficheiro existe

        If Not IO.File.Exists(imagePath) Then

            Throw New Exception("O ficheiro não existe!")

        End If

        Try

            ' Cria o ficheiro *.bmp

            Dim imgName As String = IO.Path.ChangeExtension(imagePath, "bmp")

            Dim bm As Bitmap = Image.FromFile(imagePath)

            bm.Save(imgName, System.Drawing.Imaging.ImageFormat.Bmp)

            ' Define o novo wallpaper

            SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, imgName, SPIF_UPDATEINIFILE)

        Catch ex As Exception

            Throw New Exception(ex.Message)

        End Try

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Try

            OpenFileDialog1.Filter = "(*.jpg;*.bmp;*.gif;*.png;*.jpeg)|*.jpg;*.bmp;*.gif;*.png;*.jpeg"

            OpenFileDialog1.Title = "Selecionar Foto"

            If OpenFileDialog1.ShowDialog = DialogResult.OK Then

                pictureFoto.Image = Image.FromFile(OpenFileDialog1.FileName)

                SetWallpaper(OpenFileDialog1.FileName)

            End If

        Catch ex As Exception

        End Try

    End Sub

End Class

 Espero ter ajudado e até a próxima...