title: Get Image back from CGBitmapContextGetData
body: <p>So I have a <code>CGBitmapContext</code> and I get the pixel at a touchlocation using this   </p>
  
  <pre><code>unsigned char* data = CGBitmapContextGetData (offscreenBuffer);
  
  if (data != NULL) {
      offset = 4*((self.bounds.size.width*round(coord.y))+round(coord.x));
      int alpha =  data[offset];
      int red = data[offset+1];
      int green = data[offset+2];
      int blue = data[offset+3];
  
  } 
  </code></pre>
  
  <p>And then I change the pixel colour like below.</p>
  
  <pre><code>data[offset]=255;
  data[offset+1]=255;
  data[offset+2]=0;
  data[offset+3]=0;
  </code></pre>
  
  <p>My question is how do a get a CGImage back from the modified pixels so that I can update my <code>CGBitmapContext</code>?</p>
  
  <p>Any help will be appreciated, Thanks!</p>