ASP.NET - Draw an circle on image button on click event

I have an query regarding image button . As i have a image button which loads image on page load from database by url i.e in my database i have some URL stored which displays images.

So when i click on the image, i get the co-ordinates , but on the same time i need to have a circle or some kind of marker placed on that co-ordinate were i click.

This is my code of getting co-ordinates:-

protected void ib_Click(object sender, ImageClickEventArgs e)
    {
      x = e.X;
      x = Convert.ToInt32((x / 400) * 100);
      y = e.Y;
      y = Convert.ToInt32((y / 600) * 100);
      txtxoffset.Text = x.ToString();
      txtyoffset.Text = y.ToString();
    }

How can i get an circle or any marker on that co-ordinate .

Use GDI+ to search on redrawing an image file that can be loaded into your page.  You can't draw on the image "in the browser" (at least not in those that don't support html5).  You have to recreate the image server side and then get it to render in the browser.