Header Design

I am wondering how to accomplish my goal of a balanced header. 2 images in the header background that will separate when viewed on smaller devices. Either by one image...that is fixed on the right hand side of the page and is of 500px or less and the other left image being put in as the logo image....or something. Please view my question which is fully explained at this link showing visual images of what I am asking for. http://192.185.142.81/~rawhideo/design-question/ Thanks so much