The rules regarding this are stated here, but as this concerns all areas of Manga Art, an announcement of this seems appropriate:

With the change in rules regarding spoilers, we've decided to apply these to the art sections as well for consistency's sake. This means that colorings/lineart/fanart/etc. using content from the latest chapter cannot be posted until 24 hrs after the chapter is released for all ongoing series.

Please refer to the forum rules if you have any questions, or you may contact any art or global mod via PM.

Thanks in advance for your cooperation!