At several MB's each, that could quickly eat up the course storage depending on how much your district/university provides. As an alternative, consider using a service like Google Drive or OneDrive. Make a folder for the images, change the sharing settings so that anyone with a link can view the folder, the put that link on whatever Page, Assignment, Discussion, etc. in which you want students to use the images. Make sure to keep the sharing privileges set up so students can only view, not edit. This should allow them to download any particular images if needed, without affecting the folder for others.
