You can use the Rich Content Editor to embed images from the web. You can also add alt tags to your images for better accessibility.

The Rich Content Editor is used in features that support the editor (Announcements, Assignments, Discussions, Pages, Quizzes, or Syllabus). If a change is made to the source of your image after it has been embedded, the image you have added to the Rich Content Editor will not be changed.

Note: If you want to embed an image not already uploaded into Canvas, you can upload your image through the Content Selector.