title: Simple GCD Serial Queue example like FIFO using blocks
body: <p>I read Apple documentation on how to Use serial queues to ensure that tasks to execute in a predictable order but now i am confused too much.<br>
  Some how i am able to work serially but still i am not clear so i need simple serial example for my methods to execute serially.</p>
  
  <p>I divided my functionality  in to 4 parts and now want them to execute Serially</p>
  
  <pre><code>[self ReadAllImagesFromPhotosLibrary];
  
  [self WriteFewImagestoDirectory];
  
  [self GettingBackAllImagesFromFolder]; 
  
  [self MoveToNextView];
  </code></pre>