Functional images are used to initiate actions rather than to convey information. They are used in buttons, links, and other interactive elements.
The text alternative for the image should convey the action that will be initiated (the purpose of the image), rather than a description of the image.
Missing or empty alt values create significant problems for screen reader users because functional images are essential to the functionality of the content.
Note: Using images for buttons is not a best practice. A better practices is to use of text content, since the colors and font can easily be adjusted to a users needs.
