An img element must follow the guidelines of Success Criterion 1.1.1 (Non-text Content) with regards usage of alt and title attributes.
This example tests the correct usage of alt and title attributes where the image is intended to be ignored by assistive technology. The title attribute in this case is empty. A warning is generated to alert the author to ensure that the image is not being ignored by mistake (ie. it is not purely decorative), and provide relevant alt and title attributes as required.