How can I get dynamicaly generated images from WebBrowser as Bitmap in WinForms

I want to save an image from a website that created by a PHP script. I mean every time when I open that page i got a new random image.

I load the website into a WebBrowser and I can get it's elements, but I don't know how could I get the desired image as a Bitmap.

The image's HTML looks like this: <img alt="kod" src="somerandom.php"/>

private void DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{      
    foreach (HtmlElement documentImage in webBrowser1.Document.Images)
    {
        if (documentImage.OuterHtml.Contains("alt=\"kod\""))
        {
            // i want to get this image as a bitmap
        }
    }
}

When you open the random.php it gives you another random image. I need to get that image is visible in my WebBrowser. I tried to find solution, but I got solutions those just downloads the image by the src value. That way I cannot solve this problem.

I want to put a clone of this image to a PictureBox on the screen next to the WebBrowser.

enter image description here