Anger is a strong feeling of displeasure. Another word for angry is mad. People often get angry when they don't get their way, or when someone disagrees with them. The person in the picture is angry.
You are concentrating on something if you are completely focussed on it, and have blocked out all other distractions. People usually concentrate when they are doing something complicated that requires them to think hard without being interrupted.
You feel disgust when you have a sudden, very strong dislike of something. Some smells, like rotten food, are disgusting. The person in the picture is disgusted.
