unable to cast from source to destination

here is my code i am again and again getting cast exception …please help me in this code …i am trying to capture an image and then show it …i have used gameobject cube on which i am streaming the camera feed .here is the code

using UnityEngine;
using System.Collections;

public class Selfie : MonoBehaviour {
	public string deviceName;
	WebCamTexture wct;

	// Use this for initialization
	void Start () 
		WebCamDevice[] devices = WebCamTexture.devices;
		deviceName = devices [0].name;
		wct = new WebCamTexture (deviceName, 400, 300, 12);
		renderer.material.mainTexture = wct;
		wct.Play ();

	//for photo variables

	public Texture2D heightmap;
	public Vector3 size= new Vector3(100,10,100);

	 void OnGUI()
	  if (GUI.Button (new Rect (10, 70, 50, 30), "click"))
	  TakeSnapshot ();

	//for saving to the _savepath 

	private string _SavePath= "D:/WebcamSnaps/" ;
	int _CaptureCounter = 0;

	void TakeSnapshot()
		Texture2D snap = new Texture2D (wct.width, wct.height);
		snap.SetPixels (wct.GetPixels ());
		snap.Apply ();

		//byte[] bytes = snap.EncodeToPNG ();
		System.IO.File.WriteAllBytes(_SavePath + _CaptureCounter.ToString() + ".png", snap.EncodeToPNG());

		WWW www = new WWW ("file://D:/WebcamSnaps/0.png");
		while (!www.isDone)

	    www.LoadImageIntoTexture((Texture2D)renderer.material.mainTexture) ;



Please, share the error you see, not just some words from it. If you have a cast exception it probably says why it can’t make the cast.

Also, note that this:

while (!www.isDone)


will try to load the downloaded image into a texture every frame while the request has not finished. Even if there wasn’t a cast error, this line will throw an exception.

You probably want to write this code instead:

while (!www.isDone) {} // not the brakets, the next line will be called ONLY after the request finishes


But this is really a bad idea, the game will freeze until the request ends. You should make this method a coroutine and yield until the request is done.