ALT \ Alt text
The ALT is an attribute that can be added to an HTML image tag to textually explain what is happening in the image for those who cannot see it or who use assistive technologies.
Although this attribute is not required to display the image, there is a guideline from the W3C to use this attribute properly for all accessibility levels (A, AA, AAA).
Here is an example of the ALT syntax:
<img src="policeman.jpg" alt="Policeman standing and holding a traffic sign pointing to the left" />