Old Danbooru rendered thumbnails for images with transparent backgrounds with a black background. So black lineart on a transparent background results in a solid black thumbnail. Like this one's.
Old Danbooru rendered thumbnails for images with transparent backgrounds with a black background. So black lineart on a transparent background results in a solid black thumbnail. Like this one's.
Usually when someone posts a lineart on pixiv it is either because they want to show the picture being in process or because they want to see the others color it.
Given that this image has 2 children being colored by different people and is tagged as å¡—ã‚Šçµµ on pixiv, I think it is safe to assume that the artist wouldn't mind if you want to color his/her lineart and put the image online.
And well even if the artist doesn't allow it who's to stop you from doing so anyway as long as you don't put it online.
Asking us is a bit silly. We, by definition, pretty much plagiarize things justified with attribution. The source of the image is listed; you can try asking the artist if you really care. Always heed the creed, however; uploading your own work on Danbooru is sacrilege.