After Deborah takes a picture directly into the bathroom mirror, then falls backwards into the tub, she looks at the resulting shot and it shows her in mid-fall with the camera clearly pointed at the ceiling. Even if the mirror has magical or mystic powers, the digital camera would have reproduced the image presented to the lens, not the point of view of the mirror.
In scenes where Debra is in the bathroom, her reflection at the mirror in the back shows her face in the front when clearly it should show the back of her head.