To make sure that all users can answer your form, it is important that the form is accessible by everyone. A significant amount of users need supplementary material to understand the information elements. By using only images and illustrations you risk to exclude users from answering your form.
Alternative texts help users who can not perceive images to understand the content. This may be persons who are blind, visually impaired, or those who have turned off the in the browser. Alternative texts are short and describe what the image illustrates and should not be confused with captions.
The alternative text will, in the context of answer options, be used in form reports related to the submissions the form has received. This information will also be availbale in the web report, excel report and the tab delimited file.