pictures and copyrights

What about cutting and pasting pictures from the internet? This weekend my son (a 6th grader) had a homework assignment where he had to find pictures and paste them on a science worksheet about the food chain. My first thought was does he need magazines to cut up (am I dating myself). When we would cut up magazines and use the pictures, we weren't thinking of copyrights. Anyways what about the copyrights of pictures off the internet that kids use for school assignments? My son used small images of the pictures. Would a cut and paste type of project be ok (thinking back to what we did with cutting up magazines but now it is pictures from the internet)? If it was a picture used for a report then maybe the students should be sure the copyright information is listed with the picture. Also are the rules different from what students could do at home and what the teachers could allow the students to do at school? In other words maybe teachers couldn't provide the students with pictures from the internet to cut up or allow them to find pictures on the internet at school but the students could find the pictures on the internet at home, cut them up, and bring in the completed assignment. What do you think?