如何在PHP中使用preg_replace找到最后一次出现（特定的字符串）

Question

我在一个段落中有3张图像，我想使用preg_replace访问它们，但我却得到2张图像src，但是对于最后一个或第3个preg_replace无法正常工作。

如下所示，我的代码

$data = $params['txtFirst'];

list($type, $data) = explode(';', $data);
list(, $data)      = explode(',', $data);
$data = base64_decode($data);
$Location1 = "http://First.png";
file_put_contents('First.png, $data);

// place manual value for src
$Location2 = "src="."'".$Location1."'";
$New1 = preg_replace('/src="([^\\"]+)"/', $Location2, $params['txtDesc1'], 1);

// for second image
$data1 = $params['txtSecond2'];
list($type, $data1) = explode(';', $data1);
list(, $data1)      = explode(',', $data1);
$data1 = base64_decode($data1);
$Location3 = "http://second.png";
file_put_contents('second.png', $data1);

// place manual value for src
$Location4 = "src="."'".$Location3."'";
$New2 = preg_replace('/src="([^\\"]+)"/', $Location4, $New1, 2);


// for third image
$data2 = $params['txtThird3'];
list($type, $data2) = explode(';', $data2);
list(, $data2)      = explode(',', $data2);
$data2 = base64_decode($data2);
$Location5 = "http://third.png";
file_put_contents('third.png', $data2);

// place manual value for src
$Location6 = "src="."'".$Location5."'";
$New3 = preg_replace('/src="([^\\"]+)"/', $Location6, $New2, 3);