Unity3D选择本地图片并加载

using UnityEngine;
using System.Collections;
using System;
using System.Windows.Forms;
using System.IO;
using UnityEngine.UI;
public class AddHead : MonoBehaviour {
 private Texture2D img=null;
 public Image image;
 public Sprite sprite;
// Use this for initialization
 void Start () {
 }
 // Update is called once per frame
 void Update () {
 }
 /*void OnGUI(){
 if (GUI.Button (new Rect (0, 0, 100, 20), "选择文件")) {
 }*/
 public void addhead(){
 OpenFileDialog od=new OpenFileDialog();
 od.Title="6K+36YCJ5oup5aS05YOP5Zu+54mH";
 od.Multiselect=false;
 od.Filter="图片文件(*.jpg,*.png,*.bmp)|*.jpg;*.png;*.bmp";
 if(od.ShowDialog()==DialogResult.OK){
 //Debug.Log(od.FileName);
 StartCoroutine(GetTexture("file://"+od.FileName));
 }
 /*if (img != null) {
 //GUI.DrawTexture(new Rect(0,20,img.width,img.height),img);
 image.sprite=sprite;
 }*/
 }
 IEnumerator GetTexture(string url){
 WWW www = new WWW (url);
 yield return www;
 if (www.isDone && www.error == null) {
 img=www.texture;
 sprite=Sprite.Create(img,new Rect(0,0,img.width,img.height),new Vector2(0.5f,0.5f)); 
 image.sprite=sprite;
 //Debug.Log(img.width+" "+img.height);
 byte[] date=img.EncodeToPNG();
 }
 }
}