var httpClient = new HttpClient();
using (FileStream fs = new FileStream("C:\\1.jpg", FileMode.Open, FileAccess.ReadWrite))
{
using (var content = new MultipartFormDataContent())
{
content.Add(new StreamContent(fs),"image",fs.Name);
var t23 = httpClient.PostAsync(string.Format("http://localhost:9700/api/Info/UploadImg?Token={0}&TimeSpan={1}&Sign={2}", token, timeSpan, serverSign), content).Result.Content.ReadAsStringAsync().Result;
}
}

HttpClient 发送图片