Koolk was arrested!!

Any extractions of any freely distributed data on the internet is completely legal, and it's also a fundamental right of humans to talk about it. It's called freedom of press and speech. Southperry, Sleepywood, Hiddenstreet, they all have the freedom to publicise everything they want, even if they're not even fansites at all...

Intellectual property.

Nexon distributes its client for free, sure, but it (and everything else contained within it, including images, sound files, etc) is still owned by Nexon and it's infringement to host it elsewhere in any other form. Like a png image.

They aren't likely to sue every single person who uses Maplestory images, since there's simply too many of them and Nexon doesn't stand to gain much from doing that, but I'm pretty sure it does technically constitute infringement.

Not saying I'm against it.