function swapMainImage(small_image) {
		
		var small_img1 ='', small_img2 ='';
		
		file_ext 	= small_image.substring(small_image.indexOf("."), (small_image.indexOf(".") + 4));	
		img_num 	= small_image.substring(small_image.indexOf("."), (small_image.indexOf(".") - 1));
		start_str	= small_image.substring((small_image.indexOf(".") - 1), 0);
		
		var img_1_start_pos = (document.mainBox.src.lastIndexOf("/") + 1)
		var img_1_full_str	= document.mainBox.src.substring(img_1_start_pos, document.mainBox.src.length);

		var img1_file_ext 	= img_1_full_str.substring(img_1_full_str.indexOf("."), (img_1_full_str.indexOf(".") + 4));	
		var img1_img_num 	= img_1_full_str.substring(img_1_full_str.indexOf("."), (img_1_full_str.indexOf(".") - 1));
		var img1_start_str	= img_1_full_str.substring((img_1_full_str.indexOf(".") - 1), 0);
		
		var img_2_start_pos = (document.small_img1.src.lastIndexOf("/") + 1)
		var img_2_full_str	= document.small_img1.src.substring(img_2_start_pos, document.small_img1.src.length);

		var img2_file_ext 	= img_2_full_str.substring(img_2_full_str.indexOf("."), (img_2_full_str.indexOf(".") + 4));	
		var img2_img_num 	= img_2_full_str.substring(img_2_full_str.indexOf("."), (img_2_full_str.indexOf(".") - 1));
		var img2_start_str	= img_2_full_str.substring((img_2_full_str.indexOf(".") - 1), 0);
		
		var img_3_start_pos = (document.small_img2.src.lastIndexOf("/") + 1)
		var img_3_full_str	= document.small_img2.src.substring(img_3_start_pos, document.small_img2.src.length);

		var img3_file_ext 	= img_3_full_str.substring(img_3_full_str.indexOf("."), (img_3_full_str.indexOf(".") + 4));	
		var img3_img_num 	= img_3_full_str.substring(img_3_full_str.indexOf("."), (img_3_full_str.indexOf(".") - 1));
		var img3_start_str	= img_3_full_str.substring((img_3_full_str.indexOf(".") - 1), 0);		 
		
		if (document.getElementById("small_img3")) {
				var img_4_start_pos = (document.small_img3.src.lastIndexOf("/") + 1)
				var img_4_full_str	= document.small_img3.src.substring(img_4_start_pos, document.small_img3.src.length);

				var img4_file_ext 	= img_4_full_str.substring(img_4_full_str.indexOf("."), (img_4_full_str.indexOf(".") + 4));	
				var img4_img_num 	= img_4_full_str.substring(img_4_full_str.indexOf("."), (img_4_full_str.indexOf(".") - 1));
				var img4_start_str	= img_4_full_str.substring((img_4_full_str.indexOf(".") - 1), 0);		 
		}
		
		
		if (img_num == 2) {
			document.mainBox.src='images/detail/' + img2_start_str + img2_img_num + img2_file_ext
			document.small_img1.src='images/detail/' + img1_start_str + img1_img_num + img1_file_ext
			document.small_img2.src='images/detail/' + img3_start_str + img3_img_num + img3_file_ext
			document.small_img3.src='images/detail/' + img4_start_str + img4_img_num + img4_file_ext
		}
		else if (img_num == 3) {
			document.mainBox.src='images/detail/' + img3_start_str + img3_img_num + img3_file_ext
			document.small_img1.src='images/detail/' + img1_start_str + img1_img_num + img1_file_ext
			document.small_img2.src='images/detail/' + img2_start_str + img2_img_num + img2_file_ext
			document.small_img3.src='images/detail/' + img4_start_str + img4_img_num + img4_file_ext
		}
		else if (img_num == 4) {
			document.mainBox.src='images/detail/' + img4_start_str + img4_img_num + img4_file_ext
			document.small_img1.src='images/detail/' + img1_start_str + img1_img_num + img1_file_ext
			document.small_img2.src='images/detail/' + img2_start_str + img2_img_num + img2_file_ext
			document.small_img3.src='images/detail/' + img3_start_str + img3_img_num + img3_file_ext
		}
	}