To make the task of orientating our photographs easier we have ImageFlip. It is an easy to use application that is basically composed of three elements: a side panel like a file explorer, an image previewing window and a couple of buttons that form the main controls of the application.
Once an image is open with ImageFlip, all you will have to do is click on one of the two controls: "Flip left" to rotate the image 90º to the left or "Flip right" to rotate the photograph 90º to the right. By clicking on one of these two button successively we will obtain the photograph with four different orientations and we will be able to select the one that meets our purposes.
Try ImageFlip, that easiest application to rotate your photographs.