Accessibility testing is essential not just because you want to make your website/app accessible but it is a step towards making the web inclusive.
In modern website layout, Images and Graphics are being used to attract the audience and give a better experience.
but when they don’t have alternative text, assistive technology users can’t feel the same experience and we somehow break the inclusiveness.
There are many WCAG success criteria that ensure the images and graphics accessibility one of them is WCAG Success criteria 1.1.1 Non-text content.
The most possible scenarios that should keep in mind while developing and testing a website, below are some possible scenarios where the non-text content success criterion fails.
Possible Failures of WCAG Success Criterion 1.1.1 Non-text Content
1. Informative images are presented using CSS
Informative Image used as the background image of any <div>, <span>, etc. is considered as a failure of success criterion non-text content.
Inspect the images on the page and confirm the <img> tag is not used.
2. Image missing alt attribute
<img> tag without alt attribute is a failure of success criterion non-text content no matter if the image is informative or decorative.
3. Decorative image with alternative text present
Any decorative image that holds alternative text may distract the user from actual text and decorative should be ignored by assistive technology.
Inspect the decorative image and check alt attribute is not empty, this would be a failure of success criterion non-text content.
4. Informative image with insufficeint alternative text or no alternative text present
An informative image should have alternative text to provide the convey the same information to the assistive technology users.
Inspect the image and check alt attribute hold insufficient information or the alt attribute is empty, this is a failure of success criterion non-text content.
The above 4 failures are the most possible test cases that should take place while testing for WCAG Success Criterion 1.1.1 non-text content.
If you are a developer and want to make a decision whether to provide alternative text or not use the Alt Decision Tree
Also, find out more possibilities of failure of success criteria provided by w3.org.