base64_decode() 獲取圖片的大小
$img_info = getimagesize('64點陣圖片字串');
print_r($img_info);
Array ( [0] => 198 [1] => 198 [2] => 3 [3] => width="198" height="198" [bits] => 8 [mime] => image/png )
//獲取圖片大小
$img_info = file_get_contents('64點陣圖片字串');print_r(strlen($img_info)/1024);