This depends on the layout of your web page.
A regular web page has a known width (the width of the user's browser window) but no know height (as there could be a lot of content which the user would have to scroll down to see using a vertical scroll bar).
You can horizontally center a gallery on a web page by replacing:
... in your gallery's embedding code, with:
<div id="sv-container" margin="0 auto;">
If you simply list block-level elements in a web page, such as:
... they will appear one below the other in a vertical column.
Perhaps you have elements positioned absolutely on your web page which would explain why elements overlap each other.
Take a look at this guide to CSS Positioning which should hopefully help with your web page layout.
SimpleViewer Support Team