The reactions of a dog in front of a mirror

They can spend hours in front of a mirror focusing only on their own reflections. ... On the contrary, if your companion seems fascinated by his reflection, in reality, he is only scrutinizing the behavior of the animal he sees in front of him.
When we look at ourselves in a mirror, we know that the reflected image is ours. some of the animals show signs of recognition of their mirror image.
And the dogs: how do they interpret the image reflected in the mirror? Do they know this is their own image?