Recently used this feature is wasted a lot of time. Finally, I found very simple:
Just add the following code in the onload event in the form
Private Void Mainform_Load (Object Sender, System.Eventargs E)
{
Image background = image.fromfile ("Image Path");
Image tmpback = new bitmap (background, this.width, this.height);
THIS.BACKGROUNDIMAGE = TMPBACK;
}
