This is the 276th most frequent Slovenian word.
njihove
"Their" (possessive pronoun).
The word 'njihove' is used as a possessive adjective here, indicating ownership.
Njihove knjige so na mizi.
Their books are on the table.
The word 'njihovem' is a declined form, functioning as a possessive adjective in locative case.
Oni govorijo o njihovem prijatelju.
They are talking about their friend.
The word 'njihove' indicates possession and agrees in gender and case with the noun 'slike.'