This is weird... on the main page Nu doesn't show up on the image yet when I see it on the original source or view image on another window/tab, Nu shows up o_o

Looks like a trick with transparency. If you can't see the second character while viewing the image on this page, try one of these:
If your browser has a console, run this in it:

document.getElementById("image").style.backgroundColor = "silver"

Otherwise, make a bookmark with this for the address, and click it:

javascript:document.getElementById("image").style.backgroundColor="silver";void(0)

Huzzah, now I have a way to check if an image has a white or transparent background without downloading it now that Danbooru doesn't turn it black in thumbnails.