'Alt' tag question

[Raymond Wood]

Hello everyone,

I seem to recall W3C mentioning somewhere that graphics used for
positional reasons only (e.g. 'spacer.gif') should be assigned
an 'alt' attribute like the following:
  alt=""
  
This allows HTML code to validate properly, and supposedly
increases page accessibility for those visually-challenged
persons who use 'screen-readers' and other similar tools.

Can anyone confirm or deny whether this is accurate?

Cheers,
Raymond