(Un)necessary Alt tag

Question

The course says, the alt ta is necessary for inputting an image, but my websites work without it, why?

Answer 1

alt attribute is required for <img> tags if you want your markup to validate. Background images and bullets are just cosmetic, they don't need an alternate representation as they are not part of the content.

Answer 2

text inside alt tag is displayed when the image is not supported by the browser

Answer 3

so, it's not necessary

Answer 4

then they should say so in the course

Answer 5

alt tag is intended for blind people to be read what is in the pic....it also helps with seo rankings