Using the WebBrowser control to only show specific images?

I am a complete noob at VB.NET, but was wondering if I could get help on something.

I basically need to strip entire webpages from text, script etc.. I only want the main image(s) to show.

I thought about getting the HTML source code, and using it to find the tags and only if it contains "imgur" inside of it, it'd redirect to the main image...

But I really really don't know how to pull that off...

If someone could help me on this, or even show me an easier way, that'd be amazing!!

Thanks in advance, Nathan