Optimizing a Course Image:First crop and save your course image. For Moodle themes where the image is only used on the frontpage, we recommend 600px wide x 300px tall. For Moodle themes where the course image is being used as a banner or cover inside the course, 1920px 1080 is more than enough. There are plenty of web-based services that you can use to ‘optimize’ your images but we prefer Kraken.io. The interface is easy to use. Just drag your images into the upload box, let Kraken do the work and then download them. They can often radically reduce the weight of an image.
Adding Your Optimized Image to a Moodle CourseThe next step is to add the image to the course. Login as an admin to your Moodle install. Enter the course and click on ‘Edit Settings’ under ‘Course Administration’ in the blocks area. Once in the settings scroll down to ‘Course Summary Files’. Drag your optimized image into this box, scroll to the bottom and hit save and you are done!