Display HTTP Image In HTTPS Site?

I have a https site where i have to display images from a http source. To enable this i want to make a proxy, so i can display the image as:

src="https://mydomain/showimage.aspx?url=http://externalserver/image.jpg"

I can do this in Java, somthing like this:

Code:
InputStream in = new WebInputStream( url );
BrowserOutStream out = new BrowserOutStream();
while(in.read()){ out.write() };
in.close();
out.close();

Simple enough (although the code is simplified here). But i cant seem to find a proper example of the equivalent in vb .net. I am assuming i have to use System.Net.WebClient.OpenRead, but not sure where to go from there.