Since there were no other websites like that back then, it was eventually overrun by non-IRC-users and transformed into what we'd now call a more generic social media platform. Something like the eternal September I guess. People started calling the gallery "IRC" as shorthand, which royally pissed off the original userbase. Fun times.
Then Facebook appeared and everyone moved there.
It's still up, but it's more of a historical relic these days. Not sure who, if anyone, still uses it: https://irc-galleria.net/
Wikipedia: https://en.wikipedia.org/wiki/IRC-Galleria