int i = 0;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
ImageButton1.ImageUrl = "images/2.jpg";
}
}
private void button4_Click(object sender, EventArgs e)
{
if (i == 0)
{
ImageButton1.ImageUrl = "images/1.jpg";
i = 1;
}
else
{
ImageButton1.ImageUrl = "images/2.jpg";
i = 0;
}
}