diff --git a/install/index.php b/install/index.php
index 65b5549d4..b6c140f2d 100644
--- a/install/index.php
+++ b/install/index.php
@@ -1,6 +1,7 @@
 <?php
 include_once ('../config.php');
 $title = G5_VERSION." 설치 3단계 중 1단계 라이센스 확인";
+require_once('./library.check.php');
 include_once ('./install.inc.php');
 ?>
 
@@ -17,7 +18,7 @@ if ($exists_data_dir && $write_data_dir) {
 <form action="./install_config.php" method="post" onsubmit="return frm_submit(this);">
 <div id="idx_agree">
     <label for="agree">동의합니다.</label>
-    <input type="checkbox" id="agree" name="agree" value="동의함"> 
+    <input type="checkbox" id="agree" name="agree" value="동의함">
 </div>
 
 <div id="btn_confirm">
diff --git a/install/library.check.php b/install/library.check.php
new file mode 100644
index 000000000..08889cc50
--- /dev/null
+++ b/install/library.check.php
@@ -0,0 +1,14 @@
+<?php
+if (!defined('_GNUBOARD_')) exit; // 개별 페이지 접근 불가
+
+function die_utf8($msg)
+{
+    if(!trim($msg))
+        return;
+
+    die('<meta charset="utf-8"><p>'.$msg.'</p>');
+}
+
+if(!extension_loaded('gd') || !function_exists('gd_info'))
+    die('GD 라이브러리를 설치하신 후 '.G5_VERSION.' 설치를 진행해 주십시오.');
+?>
\ No newline at end of file
diff --git a/lib/common.lib.php b/lib/common.lib.php
index d915b06aa..ee1bb82ac 100644
--- a/lib/common.lib.php
+++ b/lib/common.lib.php
@@ -1909,6 +1909,12 @@ function get_selected($field, $value)
 }
 
 
+function get_checked($field, $value)
+{
+    return ($field==$value) ? ' checked="checked"' : '';
+}
+
+
 function is_mobile()
 {
     return preg_match('/'.G5_MOBILE_AGENT.'/i', $_SERVER['HTTP_USER_AGENT']);