Firstly, the confusion that there can only be one alpha male stems from the term as used in the study of gorilla, baboon or chimpanzee societies and other related hairy primates. There are no scientific studies yet on human alpha males that have reached mainstream academia or scientific communities.
As opposed to gorilla societies which are at best one dimensional, human societies are multidimensional. Hence, multiple human alpha males can co-exist or group together. However, a first among equals or primus interpares can be voted in or established as the leader of several alpha male humans.
As to your picture, we can only pinpoint who is laid back, who has oozing self-confidence and who has an open body language but never who is the alpha male. It's just a picture.
If you've watched Band of Brothers and the guy who handled the training of Easy Company versus the guy the company relied on in times of combat, you'll see human alpha males in a new light. In World War 2, Easy Company is a bunch of alphas and the rest of the companies who were retreating and losing were betas.
A human alpha male is judged by what he does and how skillful he does the job. If you're the top guy in eating 3 dozen hamburgers while washing it down with Bud Light in 3 minutes flat, then you're alpha in that category. Meh, I would rather be alpha in eating and fucking pussy.

_________________
Approach. Open. Escalate. Isolate
Here are my two essential rules on texting that will save you tons of time and money:
general-questions/topic137931.html