How it should work
Currently when an image is inserted in Canvas the file name is automatically inserted as the ALT attribute with the IMG tag. Content creators are not aware of this unless they view the source code (the code that is generated for the image). The Rich Content Editor accessibility checker will not flag those as problematic images because it has an assigned value (a meaningless value).
A better user experience would be to pop up a window for the user to enter a value for the ALT attribute when the image is being inserted in the page. Alternatively (or in addition) when the Rich Content Editor’s Accessibility Checker is run a pop up window would appear for each image with a text box containing the current alternative text (image filename by default). This would provide the content creator with awareness and opportunity to verify and change the alternative text.
Why we shouldn't wait
Content creators are not aware of Canvas adding the image filename in the ALT tag unless they view the source code (the code that is generated for the image). The Rich Content Editor accessibility checker does not flag those images since it has a value (a meaningless value). Adding an additional automated feature that presents the current alternative text would allow the content creator to change the meaningless value. Thus, the increased awareness of the default alternative text would improve the accessibility of the content for the students.
How it benefits students
Courses with images that have meaningful alternative text can be comprehended by all students. This puts all students on an even playing field. This new feature would proactively encourage faculty and designers to add descriptive and more meaningful alternative text to images as they create courses in Canvas.