Canvas Instructure recently shared in their Community Blog Post, that the Unsplash images integration has been removed from all instances of Canvas. This integration was previously available in the Rich Content Editor (RCE) to add images. According to Unsplash, any images previously embedded within Canvas courses will remain intact with no broken links.
If you wish to continue using Unsplash, you can access those images simply by searching the free repository directly at www.unsplash.com. and download the images to your device to either upload or drag/drop into the RCE. You will, of course, still be able to upload images from the computer in Canvas within the RCE in place of Unsplash.