During the professional life of an actor, dancer, model, musician and many others talented people, they find opportunities to keep a few photos that are good for their professional portfolio but I believe they should not be the core of the profile. I will explain why here.

The casting agent when looking for a model or an actor, he or she wants to have fresh images of the person with the minimum amount of makeup or special effects. A good profile will show at least one full body image and a few headshots, preferably with a variety of expressions.

If you are a model, you may need to show more of your body, so you can get jobs that require your body characteristics. Your skin, hands, ears, nose, lips, back, legs, arms and abdomen are all important to be well presented. I would still suggest having a good variety of expressions but it is your body that matters most, in most cases. So, if you select to wear too loose clothes, regardless of how nice it is, it will hide your body form.  

If you are an actor, the same applies but in many cases, your physical characteristics are not as important as your expressions and of course your acting experience. 

If you have any special skills such as a dancer or an instrument player or a singer, you may add one or two photos showing that skill. 

Now, talking about the number of images you need in your professional profile. You have to have as many as necessary to show what you need to show and nothing more.

What I mean is if you have one fresh headshot with a good smile, you do not need to have another. It does not help you to have many portraits showing the same expression. It does not help in having two versions of the same image, one in black and white and another in colour.

If you include any phone photo was taken when you were acting or modelling or any behind-the-scenes, it may help if you include the name of the show or film. If it is a very nice photo and from a nice production, it may help. If not, the impact is not very relevant. In any case, only include your top 3 or 4 behind-the-scenes photos. Your acting experience is in the text where you can tell all the relevant details. You do not need to prove your experience in your portfolio.