Images on front page

Hi Saskin, sorry maybe my question is stupid but I´m a newbie in websites and my english is bad too. here my url : www.nordicwalkingavreselaghi.it my question: How can I change the fotos ( which btw are fantastic, the verest climbers, the prayer wheel etc... I bought the theme because I like the structure but the verest fotos appealed to my soul ;) I want to replace them with other fotos but I don´t find the function in the menu.. sorry for a maybe very stupid question, kind rgds, Kristina