Remove Thin Grey Border from Branding Image

Hi Everyone.

I'm having difficulty removing the thin grey border that is automatically places around a custom branding image. I looked in Resources and tried to modify the modern_chat.html as follows.

  <iframe id="chatImageIfr" src="$!{chat.windowParams.brandUrl}" width="$!{chat.windowParams.brandWidth}" height="$!{chat.windowParams.brandHeight}" marginwidth="0" marginheight="0" scrolling="no" frameborder="0" title="background" style="border: none;">

But that still does not work.  Can someone help me out?

Here is a screenshot of our chat window. I want to remove the border around the TELUS logo/Panda.