"A picture says a thousand words."
I'd like to amend that phrase:
"A picture says a thousand words but says nothing if you don't include alt text."
Alt text is a means of providing a visual description of what is in the image. If not included anything you are trying to portray is lost for people with blindness or a vision impairment.
I love to boost and like posts on the Fediverse but don't if there is no alt text present. It's not a hard task to do and most social web apps have the option to remind you to add alt text before you post them.
Please make your posts accessible to all and make the social web a truly inclusive environment.