Couldn't get image loaded from file in IOS

Hi, I am trying to load facebook profile picture that i have saved into device. The code is working fine in Android but not IOS. I was suffering this problem for many days. So here is my code, please help me.

 using UnityEngine;
 using System.Collections;
 using System.IO;
 using UnityEngine.UI;
 
 public class UserProfilePicture : MonoBehaviour {
     public RawImage profilePicture;
     private Texture2D texture,text;
 
 
 
     void FixedUpdate(){
         if (FbSetup.userInfoLoaded) {
             if(SPFacebook.instance.userInfo.GetProfileImage(FacebookProfileImageSize.square) != null) {
                 text = SPFacebook.instance.userInfo.GetProfileImage(FacebookProfileImageSize.square);
             }
         }
 
 
         byte[] textureByte = text.EncodeToPNG ();
         File.WriteAllBytes (Path.Combine(Application.persistentDataPath,"profilePicture.png"),textureByte);
 
         Debug.Log("Save path: " + Application.persistentDataPath + Path.DirectorySeparatorChar + "profilePicture.png");
 
         if(File.Exists(Application.persistentDataPath + Path.DirectorySeparatorChar + "profilePicture.png")){
             Debug.Log("Texture saved");
         }
                        
     }
 
     void Update(){
         StartCoroutine (Control ());
         profilePicture.texture = texture as Texture;
     }
 
 
     IEnumerator Control(){
         WWW pictureUrl;
         pictureUrl = new WWW(System.Uri.EscapeUriString("file://" + Path.Combine(Application.persistentDataPath,"profilePicture.png")));
 
         yield return new WaitForEndOfFrame();
         texture = pictureUrl.texture;
 
         Debug.Log("Loaded path: " + Path.Combine(Application.persistentDataPath,"profilePicture.png"));
     }
 
 
     void OnEnable(){
         if (GLobal.playAsGuest) {
             this.gameObject.SetActive(false);
         }
         else{
             this.gameObject.SetActive(true);
         }
     }
 
 
 
 
 }
 

Appreciate for your help, thanks!