Be careful with the articles and photos attached to your students' assignments. Your students likely feel that including those articles and photos, often found on the Internet, enhances the overall quality of their work.

Under Intellectual Property laws, it is illegal to save and store a file which belongs to somebody else. Downloading and using a text file, a photo, a drawing, or programming code without acknowledging the owner is breaking the law.

Nevertheless you should encourage your students to do research on the Internet. Warn them that they cannot copy and paste material directly into their work; instead you can teach them to make references, use quotes, and state the sources of these materials in the format of footnotes, endnotes, and bibliographies. Follow the laws yourself: when preparing handouts for students, acknowledge the creator, don't copy more than is allowed, and/or pay the required royalties.
(http://www.ipd.gov.hk/eng/home.htm)