Ok so gamemaker is supposed to scale up your app surface as much as possible without stretching it. (keeping the aspect ratio).
What's odd and is that you're supposed to have the same sized black bar on the left like you have on the right. The right one should not be bigger.
Also, despise you're displaying the size of things in both screens, the view IS smaller in the second pic. I don't understand. Screenshots are prooving that the view is changing size.
We need to see your view and scaling related code.