First thing you have to do is, once you have taken your picture, you need to ensure it is correctly orientated when you save it on your hosting site. Pictures displaying sideways is usually a sign that when the picture was originally taken, the camera was changed from portrait to landscape orientation to take it.
Most hosting sites do not automatically correct this, the user has to do it. There's usually a button function that enables you to spin a picture but you must then re save else the orientation change will be lost.