You're right, perhaps they shouldn't include the advanced version of this pose as the stock photo since many beginners or intermediate people use these asana's listings. But, if you read the "Deepen The Pose" section, it says "***If you have the flexibility****.... you can move into a deeper backbend"

As an instructor I have also been taught to do the pose in the same manner as above...Anonymous describes. However, over the years I have become aware that there are many versions of every pose. It all depends on the practitioner!

There seems to be alot of confusion in Cobra and upward facing dog pose. I see the majority of students doing these poses so wrong and putting their backs into compromised positions. WIth that said I also see your picture of cobra contradicting the way I was taught. I was taught that hips/legs on mat arms bent, hands by side and to lift with back not using arm strength so this pose is a muscular backbend. Updog is shins, knees, thighs off mat with arms straight engagind shoulder girdle, core and legs. Two very different poses. I would love to hear from you on this. Thank you.

One important point is don't try to put your weight on your hand or push through arms. Rather use your body to move upwards. Normally when you do this way your hand will remain at some angle and will not be close to 180 degree.

In reply to Maria's query - Upward dog is a forward and upward extension of the spine and cobra is a back bend (where the spine will resemble the letter C from tail to skull)