title: Button added to navigation Item always shows in blue colour
body: <p>created <code>UIBarButtonItem</code> added Power Image to it.</p>
  
  <pre><code>barBtnPower =   new UIBarButtonItem (UIImage.FromBundle ("Images/Power@2x.png")
          , UIBarButtonItemStyle.Plain
          , (sender, args) =&gt; {
  
             });
  </code></pre>
  
  <p>button added to navigation Item on right side.</p>
  
  <pre><code>this.NavigationItem.SetRightBarButtonItem (barBtn_Logout, true);
  </code></pre>
  
  <p>Issue is Power@2x.png is in green colour. but after run the application its shows in blue.</p>
  
  <p>Can any one advice what i have done wrong here.</p>