<http://schema.org/thumbnailUrl>
<https://en-us.help.blackboard.com/@api/deki/pages/7272/thumbnail>
<https://en-us.help.blackboard.com/Learn/9.1_Older_Versions/9.1_SP_12_and_SP_13/Instructor/110_Grade_Center/020_Creating_and_Managing_Grade_Center_Columns>