In the magnification equation for a thin lens, what does a negative value of m mean?

1. Magnification is defined as m = image height divided by object height, and it also equals minus the image distance divided by the object distance. 2. Images that appear upright relative to the object have positive heights and those that are inverted have negative heights. 3. So a negative m means a negative image height, which means an inverted image. 4. The size of m, taken without its sign, says whether the image is larger or smaller than the object. 5. A magnification of -2.00 therefore means inverted and twice as tall, not upside down and half as tall. _Source: OpenStax College Physics (CC BY 4.0), Ch 25 "Geometric Optics", section 25.6 Image Formation by Lenses_