<?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 = 'aaa.jpg';
        $image_info = getimagesize($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)){
          $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;?>" />