The teaching of histology has changed dramatically with virtual microscopy. Fewer students of histology spend significant time viewing slides on a microscope and instead study images available in digital slide sets, generally accessible via the internet. However, students must still be able to correctly identify the defining characteristics of tissues and cells. This article describes the classroom use of a free image annotation tool, ThingLink, to enhance the engagement of students with digital microscopic images. ThingLink presentations were used in place of in-class workshops and were posted on a web-based classroom management site. ThingLink is relatively simple for students to master and is a highly effective tool that can be used to enhance and assess students' ability to identify and characterize histologic images and to engage students in the course material.