swapMe = function() {
			var allImages = document.getElementsByTagName('IMG');
			
			for(var i=0; i<allImages.length; i++) {
				var img  = allImages[i];
				if (img.className == 'rollCall') {			
										
					function prepareRollOver(img){
						var imgSrc = img.src;
						var beginFileIndex = imgSrc.lastIndexOf('/') + 1;
						var fileName = imgSrc.substring(beginFileIndex);
						var path = imgSrc.substring(0, beginFileIndex);
						var beginExtIndex = fileName.lastIndexOf('.') + 1;
						var extension = fileName.substring(beginExtIndex);
						var imgName = fileName.substring(0, beginExtIndex - 1)
						var onImageSrc = path + imgName + "_on." + extension;
						
						var tempImage = new Image();
						tempImage.src = onImageSrc;
						
						img.offSrc = imgSrc;
						img.onSrc = onImageSrc;
						
					}
					
					prepareRollOver(img);
										
					img.onmouseover = function() {
						this.src = this.onSrc;
				
					}
		
					img.onmouseout = function() {	 
						this.src = this.offSrc;
					}
				}
			}	
		}
		window.onload = swapMe;