I know there are several techniques to improve website credibility like putting client references, portfolio (or any proof of work and its presentation) etc. Does personal photo on the website improves its credibility? For example, http://www.atulesh.com/ and http://www.adhamdannaway.com/ have personal photos on the main page. I understand that my question is general and there are different websites where having personal photos would impact credibility differently. But I'm interested in a specific case: having my photo on the personal website (as a UX designer), like those two websites above.
Credibility for a personal website is determined by a number of different factors. It is seldom the case that a person will make up their mind or establish trust based on a single factor, although if it has an important significance then it will have a greater weighting. In general, the more elements that you can add to a website to substantiate the perceived credibility, the more likely it is that you will achieve the desired outcome. However, it is not just about putting a photo on the website, but having the right type of photo.
So if you have a good photo but the rest of the website is of low quality, it is quite possible that the photo will be seen as the 'odd' one out and therefore the value of the photo in adding credibility to the website will diminish.
On the other hand, if the photo is of poor quality or is a poor representation of the person (i.e. in terms of their personality, values or brand) then it will also decrease the audience's perception of the website's credibility.
Researchers at LinkedIn, Yelp, Meetup and other sites have come to the conclusion that personal photos are important. You are selling yourself and your abilities. You are, in effect, interviewing with each new visitor. You are selling yourself. Your appearance counts.
It is a form of branding.
Take a look at StackExchange. The avatars are a form of branding. What does the avatar (or lack of one) say about the individual?
As a side note maybe I ought to put a photo up. :)