jquery slider going over top?

My slider seems to be going over the top of开发者_开发问答 the slider container? How can I limit it, or make it move at X px increments?

http://dubcanada.net/play/emma/jquery/index.html

I fixed this by resizing the initate element and then overlaying the actual background image. It appears it get the height to determine the start and end, so only way to do this was to trick the slider into thinking it is smaller then it actually is.