Take photo in unity c# - unity3d

Question

I'm trying to build a program that takes your photo and places it with a different background, like a monument or so. So far, I was able to turn the camera on when I start the project with this code
webcamTexture = new WebCamTexture();
rawImage.texture = webcamTexture;
rawImage.material.mainTexture = webcamTexture;
webcamTexture.Play();
Texture2D PhotoTaken = new Texture2D (webcamTexture.width, webcamTexture.height);
PhotoTaken.SetPixels (webcamTexture.GetPixels ());
PhotoTaken.Apply ();
However, I can't take a screenshot or photo because it always ends up all black. I've tried different codes but nothing is working. Can someone please help? Thanks
EDIT
After some tries, this is the code I have:
WebCamTexture webcamTexture;
public RawImage rawImage;
void Start () {
webcamTexture = new WebCamTexture();
rawImage.texture = webcamTexture;
rawImage.material.mainTexture = webcamTexture;
webcamTexture.Play();
RenderTexture texture= new RenderTexture(webcamTexture.width, webcamTexture.height,0);
Graphics.Blit(webcamTexture, texture);
Button btn = yourButton.GetComponent<Button>();
btn.onClick.AddListener(OnClick);
}
public IEnumerator Coroutine(){
yield return new WaitForEndOfFrame ();
}
public void OnClick() {
var width = 767;
var height = 575;
Texture2D texture = new Texture2D(width, height);
texture.ReadPixels(new Rect(0, 0, width, height), 0, 0);
texture.Apply();
// Encode texture into PNG
var bytes = texture.EncodeToPNG();
//Destroy(texture);
File.WriteAllBytes (Application.dataPath + "/../SavedScreen.png", bytes);
}
and with this next code the screenshot is taken, but it takes a photo of the whole thing, and not just a bit of the screen.
void Start()
{
// Set the playback framerate!
// (real time doesn't influence time anymore)
Time.captureFramerate = frameRate;
// Find a folder that doesn't exist yet by appending numbers!
realFolder = folder;
int count = 1;
while (System.IO.Directory.Exists(realFolder))
{
realFolder = folder + count;
count++;
}
// Create the folder
System.IO.Directory.CreateDirectory(realFolder);
}
void Update()
{
// name is "realFolder/shot 0005.png"
var name = string.Format("{0}/shot {1:D04}.png", realFolder, Time.frameCount);
// Capture the screenshot
Application.CaptureScreenshot(name, sizeMultiplier);
}
}

Answer 1

You can take a screenshot like this in Unity
Application.CaptureScreenshot("Screenshot.png");
Reference
EDIT 1
To take a screenshot on a specific part of the screen use the following script:
var width = 400;
var height = 300;
var startX = 200;
var startY = 100;
var tex = new Texture2D (width, height, TextureFormat.RGB24, false);
tex.ReadPixels (Rect(startX, startY, width, height), 0, 0);
tex.Apply ();
// Encode texture into PNG
var bytes = tex.EncodeToPNG();
Destroy(tex);
File.WriteAllBytes(Application.dataPath + "/../SavedScreen.png", bytes);
Reference