You may have caught this discussion, about a popular facebook page's inappropriate reuse of images (http://blogs.scientificamerican.com/compound-eye/2013/04/23/facebooks-i-fcking-love-science-does-not-fcking-love-artists/).
Here's a good rule, which I learned from a copyright lawyer, "The golden rule: Just because it’s on the internet doesn’t give your permission to reuse it."
With that in mind, are you doing enough to teach your students about the appropriate appropriation of images? Of course, you teach them how to find and cite articles, but what messages do you give them about crediting image souces?
Talk to your students about the importance of crediting the work of others. Written class work or talks that are shared only in the classroom should cite all image sources. Work that is to be published, whether in a journal or online, needs a more formal approach, which often includes getting permission from the copyright holder.
Here are a couple of tips about sourcing images for publication that I shared at a science communication workshop.
If you want to reuse an image from an image database, be sure to adhere to their requests – some want you to write for permission, others do not. I always include a credit and a link to the source – it’s polite, and gives credit where credit is due.
A few that are good sources of (usually) free images, with attribution:
Centers for Disease Control and Prevention - http://phil.cdc.gov/Phil/home.asp
Forestry Images – http://www.forestryimages.org/log.cfm
The Higher Education Academy Center for Bioscience ImageBank (Animals, plants and other) http://www.bioscience.heacademy.ac.uk/imagebank/
Clip art - http://openclipart.org/
Searchable free photos - http://www.bigfoto.com/
Images in the Teaching Tools in Plant Biology slides cite back to their original sources, and can be a good place for students to find sourced images http://www.plantcell.org/site/teachingtools/teaching.xhtml
The images illustrating Wikipedia articles are almost always available through a Creative Commons license. Wikipedia also maintains a list of public domain image resources here:
Learn about the Creative Commons license here: http://en.wikipedia.org/wiki/Creative_Commons_license
Images from scientific journals are copyright protected. You can often use them for educational purposes without paying a fee, but you must obtain permission first. Look for the Rights and Permissions link, usually on the abstract page of an article, but sometimes on the general journal information pages. Many journals use the Copyright Clearance Center service to manage their permissions - you have to register. Some journals cover all their content by a Creative Commons license and do not require a copyright clearance center request (but do require attribution). Notably, JBC and the PLOS and BMC journals are covered by creative commons licenses.
I wasn't taught about the electronic sharing of images when I was a student, because we didn't have the internet (as we know it) when I was a student, but our students live in in a more complex world - don't send them out unprepared!
Via Mary Williams