Just a heads up
There are several angry pixiv artists on twitter and 2ch that complain about people taking their art without permission, edit them, and sometimes put watermarks on them. Even if they get credit, they didn’t ask for permission. And I’m sure you wouldn’t want your art to be edited, because that gives a negative impression towards the original artwork (Or so some illustrators think)
There was one thread on 2ch that started a small movement to have Pixiv’s regulations, making it only accessible to people inside Asia, until the US site was opened.
Though there are very few people who do ask for permission, even if there’s a language barrier, the illustrators will try to communicate back to the person.