An Interactive Picture: thinglink.com
Thinglink is a free website that allows you to upload images and then make them interactive. Comments can be added, video links can be added, and this can be either collaboratively or purely for viewing sake.
The images can then be embedded on your class website.
I have used it for posting a picture to my class on our website. The class then had to click on the picture and write a comment on a specific location. The students enjoyed it and it was interactive.