My issue is I do not know how to rotate an image. The picture is a JPEG and Blender keeps loading them improperly, so I need to correct with rotation. How do I do that?
In some cases a 'backplate' is required to introduce a background color or crop the image. To mix both images you can use a Mix Node and enable Include Alpha of second input by clicking on icon right beside the 'blend-type' of that node. Create another Image Node or create an 'empty plate' via Mask Node. Plug the 'foreground' into the lower socket and the 'background' into the upper one:
Note: Always make sure that the Render Dimensions are correct in order to get the desired output: