Here's the issue,

1. Blank slide
2. Select Insert shape and choose FreeForm
3. Create a square but at an slight angle so it's not straight on but slightly askew to the right.
4. Right click on shape and choose format shape
5. Under Fill select picture and insert picture or graphic and not a color
6. As you can see the picture is not the same aspect ratio as the the original flat image.
The image is slightly off anytime you are not using a shape that is one dimensional. Anytime you use any type of X, Y or Z rotation on that image it will still display as a flat image in your three dimensional box. This displays as slightly out of alignment. My question is how can you place any graphic image into a shape and have it display in alignment with what ever angle your shape is.