寫了一天，就寫了這麽點代碼，湊後用吧。

<?php
/**
 * @filename saveImage.php
 */
function getImgName($url)
{
    if (!preg_match(‘/\/([^\/]+\.[a-z]{3,4})(\?.*?)?$/i‘,$url, $matches))
    {
        return null;
    }

    $image_name = strtolower($matches[1]);
    return $image_name;
}

function saveImage($url, $path)
{
    
 
global $debuger;

    $handle = curl_init ($url);
    /* 顯示響應頭信息 */
    curl_setopt($handle, CURLOPT_HEADER, true);
    curl_setopt($handle, CURLOPT_RETURNTRANSFER, 1);
    $img = curl_exec ($handle);
    $file_size = curl_getinfo($handle, CURLINFO_SIZE_DOWNLOAD);
    $http_code = curl_getinfo($handle
 
, CURLINFO_HTTP_CODE);
    curl_close ($handle);
    list ($header, $body) = explode("\r\n\r\n", $img, 2);
    wlog ("http code: $http_code");

    if ($http_code == 301 || $http_code == 302)
    {
        wlog ("[$url]重定向...");
        $matches = array();
        if (!preg_match(‘/(Location:|URI:)(.*?)\n/‘, $header
 
, $matches))
        {
            wlog (‘解析頭信息失敗，結束。‘);
            return false;
        }
        $redirect_url = trim(array_pop($matches));
        $url_parsed = parse_url($redirect_url);
        if (isset($url_parsed))
        {
            wlog ("已獲取重定向地址[$redirect_url]，\n正在跳轉...");
            return saveImage($redirect_url, $path);
        }
        else
        {
            wlog (‘獲取重定向地址失敗，結束。‘);
            return false;
        }
    }
    elseif ($http_code == 200)
    {
        wlog (‘請求成功...‘);
    }
    else
    {
        wlog (‘無效的請求，結束。‘);
        return false;
    }

    $image_name = getImgName($url);

    if ($image_name == null)
    {
        if (preg_match (‘/Content-Disposition:.*?filename="([^"]+)".*?\n/‘, $header, $matches) && !empty($matches[1]))
        {
            $image_name = $matches[1];
        }
        else
        {
            wlog (‘無效的圖片地址！‘);
            return false;
        }
    }

    if (!file_exists ($path))
    {
        wlog ("目錄$path不存在，正在創建...");
        if (mkdir ($path))
        {
            wlog (‘目錄創建成功...‘);
        }
        else
        {
            wlog (‘目錄創建失敗，結束。‘);
            return false;
        }
    }

    $file_path = rtrim ($path, ‘/‘) . ‘/‘ . $image_name;
    $fp = fopen ($file_path, ‘w‘);
    $length = fwrite ($fp, $body);
    fclose ($fp);

    if ($length)
    {
        wlog ("文件保存成功！\n大小: $length\n位置: $file_path");
    }
    else
    {
        wlog (‘文件保存失敗。‘);
        return false;
    }

    return true;
}

function wlog ($msg, $file_path = ‘‘)
{
    if (empty ($file_path))
    {
        $file_path = ‘log/save_img.log‘;
    }

    if (!file_exists (dirname ($file_path)))
    {
        if (!mkdir (dirname ($file_path)))
        {
            die(‘can not create directory‘ . dirname ($file_path));
        }
    }

    $fp = @fopen ($file_path, ‘a‘);
    flock ($fp, LOCK_EX);
    fwrite ($fp, $msg . "\n");
    flock ($fp, LOCK_UN);
    fclose ($fp);
}

調用的時候直接用saveImage($url, $path)就可以了。

寫了個測試的腳本，把常用的圖片格式都試了一遍，都可以通過

<?php
/**
 * @filename test.php
 */
define(‘PATH‘, ‘download/‘);
require(‘class_inc/downloadImg.php‘);
$img_list = [‘png‘ => ‘http://www.freepngimg.com/download/facebook/1-2-facebook-download-png.png‘,
             ‘gif‘ => ‘https://kanimg.9ku.com/Article/20170725/1500953725469381.gif‘,
             ‘jpg & redirect‘ => ‘http://pic2116.ytqmx.com:82/2017/0725/37/4.jpg‘,
             ‘jpeg‘ => ‘https://upload.wikimedia.org/wikipedia/commons/thumb/5/52/Soviet_BMP-1_IFV.JPEG/300px-Soviet_BMP-1_IFV.JPEG‘,
             ‘gif‘ => ‘http://n.sinaimg.cn/sports/transform/20170906/W34l-fykpyua5747968.gif‘,
             ‘jpg with params‘ => ‘http://img.freepik.com/free-icon/bmp-image-file-type-outlined-interface-symbol_318-72075.jpg?size=338&ext=jpg‘,
             ‘webp‘ => ‘http://www.gstatic.com/webp/gallery/1.webp‘,
             ‘bmp‘ => ‘http://samples.fileformat.info/format/bmp/sample/4cb74cda027a43f3b278c05c3770950f/MARBLES.BMP?AWSAccessKeyId=0V91BEFA7GM093MEVMG2&Signature=t18N8JiZUw0QOd%2FZcyK8oZAwUWk%3D&Expires=1505213123‘,
             ‘bmp1‘ => ‘http://cfile8.uf.tistory.com/image/167475304C879B427393BA‘
            ];

foreach ($img_list as $type => $url)
{
    echo "download image $type:";

    if (test($url, PATH))
    {
        echo "done\n";
    }
    else
    {
        echo "failed\n";
    }

}

function test($url, $path)
{
    saveImage($url, $path);
    $file_name = getImgName($url);
    $file_path = rtrim($path) . ‘/‘ . $file_name;
    if (file_exists($file_path))
    {
        return true;
    }

    return false;
}

php下載圖片到本地