As part of a course I teach, I ask my students to create infographics. As long as I don't post them openly, it is okay for me to keep good and bad examples of previous students' work in order to share them with my current class.

This year, I'm asking my students to upload their infographics to an open repository. As long as I don't require students to put their full names on the infographics, I don't need to worry about privacy issues.

The open sharing of the infographics is really important to the subject of the course. A student can choose not to do it, but they will miss out on the open scholarship and publishing aspect of the assignment.  I feel like I need to make any alternative assignments be worth 10% less than the open assignment. That is fine - right?