thanx filippo, changing the background image worked for me although i had to change:
imageBrush.ImageSource = New BitmapImage(uri)
to:
imageBrush.ImageSource = New System.Windows.Media.Imaging.BitmapImage(uri)
but playing audio doesnot work, stream is not decleaired it says, maybe need to import something
but i also would like to play a mp3 file because it is background music and wav would be to big. if i choose mediaelemt from the toolbox
i can add the file to it and then auto play and it is playing but only once, i will need to find a way to loop it..