the issue is that the gallery dynamicly changes the width of the outerwrapper element.
the site sculptor design also has an outer wrapper element.
in the page look for the following:
<div id="headerCap"></div>
<div id="outerWrapper">
and give the outer wrapper a unique name:
<div id="headerCap"></div>
<div id="myouterWrapper">
you will then need to go into the sitesculptor_assets/content/css/content.css file and change all of the "outerWrapper" references to "myouterWrapper"