Under fair dealing you may include another person’s work, including images, in your PowerPoint presentations that you display to students enrolled in your course. You can copy and display an entire single image from a collection of images (e.g. a single photograph from a book of photographs), or up to 10% of a stand-alone image that is not part of a larger collection. You may also put this image in Canvas.
Under the educational institution exceptions in the Copyright Act, you may display an entire stand-alone image that is not part of a larger collection of images. To do so you must ensure that there is not a commercially available copy (obtainable within a reasonable time and price) in the format required (S29.4 of Copyright Act). If you subsequently put this image in Canvas, you must destroy/remove the file from Canvas within 30 days of the end of the course. Simply making the file inaccessible is insufficient. (See S30.01 of the Copyright Act).
See the Copyright Office's infographic for details.