Image tags are classified into entity tags and abstract tags. There are more than 3,000 types of entity tags and more than 1,000 types of abstract tags.

• Entity tags include humans, animals, plants, food, vehicles, daily life, actions, scenes, weapons, medical care, education, and others.
• Abstract tags include finance and business, science, beliefs, emotions, social activities, events, society, and life.

Some tags are further classified into subtypes. The following figure shows the tag types and subtypes.

Figure 1 Tag types