.png images not loaded in iPhone

Sometimes when you may have some images displayed in your iPhone simulator and when you try to deploy it in iPhone the images may not be displayed.
      One reason which may cause this situation is for the sake of having .png images in your app, you might have changed all the other type of images (jpg or any type ) directly through  "Get Info" option. And at this case your image will be displayed in simulator and not in iPhone.