Is it illegal to make someone else's photo into an expression pack?

It is illegal to send other people's photos online, which violates the right of portrait, but it does not mean a crime, depending on the purpose of the other party. It may be illegal if the other party does this for profit.

Legal objectivity:

Article 10 18 of the Civil Code stipulates that natural persons have the right to portrait, and have the right to make, use, disclose or permit others to use their own portraits according to law. Portrait is the external image of a specific natural person that can be recognized on a certain carrier through images, sculptures, paintings, etc.