Below script is working for my png files, so just change your file extestion from jpg to png on server, and also change in url of below script, Hope this will work.
using UnityEngine;
using System.Collections;
public class image : MonoBehaviour {
Texture myImage;
// Use this for initialization
void Start () {
string url="http://www.jxysh.cn/upload/1409091854047652145.jpg";
StartCoroutine (getImage (url));
}
IEnumerator getImage (string url)
{
print ("Started");
WWW www = new WWW (url);
yield return www;
//In myImage u will get your image
myImage = www.texture;
gameObject.renderer.material.mainTexture = myImage;
}
}