First question. Did the image upload?
Secondly. Shot a bunch yesterday and the subjects are all over powered by the bright snow. Shot on full auto with scene for snow an sand, D5500 with 55-200m lens.
The way that light meters work is to try to make all things come out middle gray intensity. This makes the snow be a special problem (white background), it will underexpose to come out gray. That makes the dog dark. About +1 EV Exposure Compensation would have been a good general thing to do for Auto mode in the snow.
To correct it now, just boosting the JPG is just more problem. But if you have an Adobe Editor (Elements or Photoshop), they have this
Levels control (CTRL L). This is the standard histogram tool in many editors (even Faststone has it, menu Colors - Adjust Levels or CTRL L).
Lowering the White Point makes it brighter, but clips badly, just does not come out good here.
But lowering the center point (as marked, raises the center and lower tones, basically it boosts gamma) is brightness which does not change the end points (does not clip). This is an extremely standard tool, good to know.
In this histogram, the large peak is the snow. The smaller middle peak is the shaded upper right corner, and the lowest peak is the dog.