header('Content-type:text/html;charset=utf-8');
//读取图片文件，转换成base64编码格式
$image_file = '1.png';
$image_info = getimagesize($image_file);

// $base64_image_content = "data:{$image_info[‘mime‘]};base64," . chunk_split(base64_encode(file_get_contents($image_file)));
$base64_image_content = "data:{$image_info['mime']};base64," . 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, $result)){
    var_dump($result);
    $type = $result[2];
    $new_file = "./test.{$type}";
    if (file_put_contents($new_file, base64_decode(str_replace($result[1], '', $base64_image_content)))){
        echo '<img src='.$new_file.'>';
    }

}

array(3) {
  [0]=>
  string(22) "data:image/png;base64,"
  [1]=>
  string(22) "data:image/png;base64,"
  [2]=>
  string(3) "png"
}