On instagram, you can upload pictures for people to see. They can like your photos and comment on them. You can also use instagram to promote yourself. This is especially convenient for models.
Pros
1. Promote yourself
2. Look for inspirations
3. Stalk others' pictures
4. Share your pictures with others
Cons
1. Become conceited
2. Become insecure
3. Time consuming
4. Pediphiles
5. People can post/ send nudes