A girl often secretly uses pictures posted by others and claims that they are her own. What does it mean?

It shows that he is a person who plagiarizes the fruits of other people's work. People should be on guard against this. Maybe he is too young and ignorant to understand that this is a patented thing and cannot be Apply it casually, unless it is a public product or others allow it to be used, otherwise, if it is for profit, it is an unfair means