Is buying or owning a yearbook allowed?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger. 

You did not clarify the nature of the yearbook in question. If you are referring to the yearbook issued by institutions, countries, or companies documenting the annual events, activities, and achievements, then the basic principle is that there is no harm in buying it as long as the content is lawful. Even if we assumed that some of these yearbooks contain pictures which feature some sort of impermissible intermixing between men and women or impermissible exposure of women's adornment, this does not prevent buying such yearbooks and benefiting of them if these pictures are not intended in and of themselves.

Shaykh Ibn ʻUthaymeen was asked about the religious ruling on selling scientific books which contain pictures. He answered:

“Books which contain pictures are of two kinds: those which are made for the purpose of the pictures, such as that Burdah magazine (a fashion magazine), of which it is not permissible to buy or keep it because the purpose behind it is the pictures; and another kind, which is not made for the purpose of the pictures, rather, it has some useful purpose, but it may contain a picture of the person who wrote the article. There is nothing wrong with keeping these because it is difficult to avoid them and difficult to go through them and erase all the pictures. Moreover, it is permissible to sell them because if it is permissible to use them, it is permissible to sell them. However, if these pictures are of women, then the religious ruling depends on the purpose for keeping them: Are you buying the books for the pictures?”

Allaah knows best.