It's interesting to see the validation for Hacker News: http://w3clove.com/sitem...

DanBC · on June 16, 2012

They are functional. They need an alt tag. Having [grayarrow.gif] and [graydown.gif] is sub-optimal.

TazeTSchnitzel · on June 16, 2012

While we're at it, we should stop using tables, too.

olavk · on June 16, 2012

It is probably the up/down arrows.

jaimeiniesta · on June 16, 2012

sure, it's the arrows. Should this be done with characters, instead? Maybe CSS? This would be indeed a good case of using "alt"... alt="vote up", alt="vote down"

mistercow · on June 16, 2012

I think most of those are up/down arrows.