It would be awesome to create a photo album or gallery feature, where teachers (and students, if given permissions) can create albums and share photos.
For example, a photography club could upload their work, and other members could view and like/comment on them. A teacher could create an album of images related to schoolwork, and students could view, analyze, and like/comment on them. Teachers could upload photos of events throughout the year, and students could show off their work to their family and friends directly from their Canvas app.
Currently I use a discussion to do this, but it is not as user-friendly and the students don't view it the way they would view a photo album!