php读取和保存base64编码的图片内容

<?php
header('Content-type:text/html;charset=utf-8');
//读取图片文件，转换成base64编码格式
$image_file = './4296762_165319032930_2.jpg';
$image_info = getimagesize($image_file);
$base64_image_content = "data:{$image_info['mime']};base64," . chunk_split(base64_encode(file_get_contents($image_file)));
//保存base64字符串为图片
//匹配出图片的格式
if (preg_match('/^(data:\s*image\/(\w+);base64,)/', $base64_image_content, $result)){
  $type = $result[2];
  $new_file = "./test.{$type}";
  if (file_put_contents($new_file, base64_decode(str_replace($result[1], '', $base64_image_content)))){
    echo '新文件保存成功：', $new_file;
  }
}
?>
<img src="<?php echo $base64_image_content;?>" />
<title>Image to Base64 String</title>
<fieldset>
    <legend>Image to Base64 String</legend>
        <center>
        <form name="select_all">
                 <?php
                    echo"<h3><p>Image</p></h3>";
                    //$file = File Image yang ingin di encode
                    //Filetype: JPEG,PNG,GIF
                    $file = "encode.jpg";
                    if($fp = fopen($file,"rb", 0))
                    {
                    $gambar = fread($fp,filesize($file));
                    fclose($fp);
                    
                    $base64 = chunk_split(base64_encode($gambar));
                    //Result
                    $encode = '<img src="data:image/jpg/png/gif;base64,' . $base64 .'" >';
                    echo $encode;
                    }   
                ?>
                <br><textarea name="text_area" rows="20" cols="70"> <? echo $encode; ?> </textarea>
                <p><input type="button" value="Select All Code" onClick="javascript:this.form.text_area.focus();this.form.text_area.select();"></p>
        </form>
        </center>
    </fieldset>