Since copyright has come up I thought I would share this recent story....
A site emailed me requesting a link on Incredible Art Department..... I
evaluated the site and found one image in particular that fit a new lesson I
added (it was a drawing of the back of head - just a line drawing - and name
of artist was not given). I emailed the site that I did provide a link on
the Art Lesson Plan page on IAD (as I did see images that could inspire
lessons - I no longer add gallery listings). I asked for permission to put a
thumbnail of the image I found on the back of the head lesson plan (as an
adult example - drawing from observation).
Their reply back to me was that I could use the image for a $50.00 user
fee - They thought that would be fair - or I could purchase the drawing from
the artist for a couple hundred dollars.
My advice to you -- if you find that site and want to show your students any
of the art - is to "just do it" (you do have "fair use" - my request did not
fall under fair use technically since I was asking to "publish" the drawing
on a plan - even though it was not for profit and for educational purposes).
I did tell them that art teachers can not afford to pay $50.00 to use their
images in class and that I would be happy to remove the link at their
request... She told me to keep the link.... which gives you permission to
show the images in PowerPoint.