var imagesLoaded = false;

var images = new Array(
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'http://www.law.unlv.edu/library/images/butt_alumni_over.gif',
'http://www.law.unlv.edu/library/images/butt_alumni.gif',
'http://www.law.unlv.edu/library/images/butt_barInfo.gif',
'http://www.law.unlv.edu/library/images/butt_barInfo_over.gif',
'http://www.law.unlv.edu/library/images/butt_calendar.gif',
'http://www.law.unlv.edu/library/images/butt_calendar_over.gif',
'http://www.law.unlv.edu/library/images/butt_careerServices.gif',
'http://www.law.unlv.edu/library/images/butt_careerServices_over.gif',
'http://www.law.unlv.edu/library/images/butt_clinic.gif',
'http://www.law.unlv.edu/library/images/butt_clinic_over.gif',
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'http://www.law.unlv.edu/library/images/butt_communityService_over.gif',
'http://www.law.unlv.edu/library/images/butt_contact.gif',
'http://www.law.unlv.edu/library/images/butt_contact_over.gif',
'http://www.law.unlv.edu/library/images/butt_extranet.gif',
'http://www.law.unlv.edu/library/images/butt_extranet_over.gif',
'http://www.law.unlv.edu/library/images/butt_facultyStaff.gif',
'http://www.law.unlv.edu/library/images/butt_facultyStaff_over.gif',
'http://www.law.unlv.edu/library/images/butt_home.gif',
'http://www.law.unlv.edu/library/images/butt_home_over.gif',
'http://www.law.unlv.edu/library/images/butt_library.gif',
'http://www.law.unlv.edu/library/images/butt_library_over.gif',
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'http://www.law.unlv.edu/library/images/butt_journal_over.gif',
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'http://www.law.unlv.edu/library/images/butt_newsEvents_over.gif',
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'http://www.law.unlv.edu/library/images/butt_unlv.gif',
'http://www.law.unlv.edu/library/images/butt_unlv_over.gif',
'http://www.law.unlv.edu/library/images/butt_welcome.gif',
'http://www.law.unlv.edu/library/images/butt_welcome_over.gif'
);

for(loop = 0; loop<images.length; loop++){
  var image = new Image();
  image.src = images[loop];
}

imagesLoaded = true;

function swapImage(){
  if (imagesLoaded) {
    document[swapImage.arguments[0]].src = [swapImage.arguments[1]];
  }
}