Have a look to the following example:
It is just displaying a rotated image. As you can see in the viewer, the rotated image seems a bit distorted. You can flip between the “looks ok” and “looks strange” coordinates (the only difference is the width of the rectangle, changing the lower left coordinate longitude slightly) and you will check that depending on the coordinates the image looks good or not.
What’s the algorithm that you use to rotate the image?