vue：上傳圖片實際上是獲取圖片二進位制流，並通過base64加密，前頭會加上data:image/png;base64,帶有然後傳給後臺
     類似：data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAANIAAAFYCAYAAAA

php: 去掉data:image/png;base64,並base64_decode解密
      base64_decode('data:image/png;base64', '', $base64_image_content)))
  

$file = "./public/aaaaaaaaaaa.png";
$file2 = "./public/bbbbbbb.png";
$aaa = base64_encode(file_get_contents($file));
$bbb = base64_decode($aaa);
file_put_contents($file2,$bbb);

參考：https://blog.csdn.net/qq_38086247/article/details/82229979