Hello Yan,
as i know, dynamic resizing of the HTML-Component is not available.
Possible solution in your case:
Generating 2x different sized HTML-Components and use the right one related to the page you are actualy on and hiding the not used HTML-Component at current moment.
You can do a lot of things inside the HMTL-Component (iFrame), but you can’t do a lot with the iFrame itself.
But because my last visit was already a while ago, perhaps already some things have changed and new possibilities are already given, who knows.