cool. I see. Although the images it is referencing do not exist within that folder now. For example,
http://girlsnightoutdesigns.com/gtest/girlsnight/girlsnight/images/nav_pic-nav_cigarboxes_over.gif.
If it was one above inside gtest instead of gtest/girlsnight; or you uploaded the images with the appropriate folders so that the javascript can find them, perhaps.
Also try removing the if preloaded part temporarily. This should help a lot in finding out if the images are correctly referenced. Within function changeImages() remove the... && (preloadFlag == true) ...part. And remember to put it back when finished testing.
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EDIT: I updated the link to the example gif, I referred to the wrong image.