Yep, the original photo shows a cougar track and pretty clearly so.
FWIW a cougar hind foot below. One toe is longer than the others, much like the fingers on a man's hand, and you can tell whether the track is from the left or right foot. The heel has three lobes, which show up faintly in the pic that started this thread, but are clearly there.
A northern wolf track below. Canines tend to show claws strongly, and the two front toes are of equal length or close to it rather than one significantly longer than the other like a cat. You can see the track better if you squint.
Below is a cougar track showing at least one claw. Claws showing or not is not an always or never proof with wild animals. As someone already said, the depth and nature of the tracking medium can make the difference in whether a claw shows. So can steepness of terrain, whether the animal is running, walking, turning, adding traction... all make a difference in whether a cat will extend claws that show in a track. Likewise canines can fail to show a claw due to several factors.
And for comparison, a lynx track below. In shallow snow or light dust, a lynx usually shows a slightly fuzzy "halo" around the track caused by the fur around its foot. You can also see the lynx track clearer in this photo if you squint. The pattern made by several consecutive tracks is the surest distinction to me between a smallish cougar and a lynx. A single track may be harder to identify.
The bottom of a lynx foot shown below.
