将图像上载到服务器以供iOS下载

Question

我正在尝试将图像上传到我的服务器，然后在iOS中将其下载到应用程序中。当我使用java上传/下载时，它可以正常工作，但是当我在iOS中下载时，图像会变黑。此外，当我在浏览器中查看图像时，它上面有紫色色调，使我确信图像已损坏。我没有正确上传图片吗？

代码：

public void uploadToServer（）{

    String server = "ip";
    int port = 21;
    String user = "name";
    String pass = "pass";

    FTPClient ftpClient = new FTPClient();

    try {

        ftpClient.connect(server, port);
        ftpClient.login(user, pass);
        ftpClient.enterLocalPassiveMode();

        ftpClient.setFileType(FTP.BINARY_FILE_TYPE);

        ByteArrayOutputStream os = new ByteArrayOutputStream();

        int w = 765;
        int h = 503;
        double d = .85;
        BufferedImage img = resize(client.methods.getClientImage(),
                (int) (w * d), (int) (h * d));

        ImageIO.write(img, "JPG", os);
        InputStream inputStream = new     ByteArrayInputStream(os.toByteArray());

        String secondRemoteFile = "directory";

        // System.out.println("Start uploading file");
        OutputStream outputStream = ftpClient
                .storeFileStream(secondRemoteFile);

        byte[] bytesIn = new byte[4096];
        int read = 0;

        while ((read = inputStream.read(bytesIn)) != -1) {
            outputStream.write(bytesIn, 0, read);
        }

        inputStream.close();
        outputStream.close();
        ftpClient.completePendingCommand();

    } catch (IOException ex) {
        System.out.println("Error: " + ex.getMessage());
        ex.printStackTrace();
    } finally {
        try {
            if (ftpClient.isConnected()) {
                ftpClient.logout();
                ftpClient.disconnect();
            }
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

Heres紫色色调：

iOS代码：

- (void) refreshImage {
 client.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:    [NSURL   URLWithString:@"http://link.jpg"]]]; ;
}