If you are using SimpleViewer v2, then please see this FAQ:
Please see this FAQ:
When I view my gallery I see a grid of thumbnails, not the layout I specified. Why?
If you are using SimpleViewer v1, then the first thing to do would be to validate the code on your web page to ensure that there are no errors. You can check your web page's code with the W3C Markup Validation Service and then fix any errors reported. Once your web page's code validates correctly, it should be rendered with greater predictability and consistency across different browsers.
Also, if using a percentage height for your gallery, make sure that all parent containers of your gallery have heights specified via CSS. Otherwise, try using an absolute pixel value for your gallery's height rather than a percentage.
If you continue to experience difficulties, please post the URL to your gallery so that I can take a look and help further.
SimpleViewer Support Team