使用webrequest上载文件

我正在尝试将图像上传到图像主机http://uploads.im/。

根据其简短的API http://uploads.im/apidocs，这是一种实现这一点的方法：

http://uploads.im/api?upload=http://www.google.com/images/srpr/nav_logo66.png

注意，在这个例子中，他正在从互联网上传一张图片，而我正试图从我的电脑上传一个文件。

代码：

public ActionResult SaveUploadedFile()
{
    //Converts the image i want to upload to a bytearray
    Image postData = img;
    byte[] byteArray = imageToByteArray(postData);                
    //Is this adress not correct maybe? Is there a way to test?
    WebRequest wrq = WebRequest.Create("http://uploads.im/api?upload=");
    wrq.Method = ("POST");
    //Im thinking that here I need som code
    //that specifys the file i want to upload (bytearray)
    using (WebResponse wrs = wrq.GetResponse())
    using (Stream stream = wrs.GetResponseStream())
    using (StreamReader reader = new StreamReader(stream))
    {
        string json = reader.ReadToEnd();
        tempJson = json;
    }
}

请看！谢谢

EDIT，新代码：

string filepath = @"c:'Users'xxxx'Desktop'Bilder'images'blank.gif";
using (WebClient client = new WebClient())
{
    client.UploadFile("http://uploads.im/api?upload", filepath);
}

我得到错误：：底层连接关闭

尝试捕获编辑：

string filepath = @"c:'Users'xxxx'Desktop'sack.png";
using (WebClient client = new WebClient())
{
    try
    {
        client.UploadFile("http://uploads.im/api?upload", filepath);
    }
    catch (Exception e)
    {
        throw new ApplicationException(e);
    }
}

private void UploadImage(string filepath)
{
    using(WebClient uploader = new WebClient())
    {
        try
        {
            uploader.UploadFile(new Uri("http://uploads.im/api?upload"), filepath);
        }
        catch(Exception ex)
        {
            MessageBox.Show("An error occured :('r'n" + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
}