I just cannot see why educational activities in primary/secondary schools are considered commercial while those in tertiary non-commercial.
There are two concerns about the use of extracted materials for educational activities: plagiarism and copyright infringement. Referencing can only protect you from the allegation of former. The focus of current discussion is on the copyright issue. The copyright owner will sue you if he’s found his right is breached and it is cost effective to do so. The presence of citation is not going to immune you from getting into trouble.
For initial question raised by rawong, the three feasible ways are
1.Draw the picture by yourself
2.Look for permission – Wikimedia or other similar sources are the choices as permission to use is readily available.
3.Copy and use it illegally – the copyright owners are not going to sue you because financial incentive is lacking.
I think I am experiencing déjà vu now. What I was talking are the current practices and none of them is my own theory. You can easily verify them if you have 10+ Oxbridge/Harvard/MIT graduates as your subordinates. I don’t mind if my words are considered incredible by others. Good bye!