Do you ask the artist or commissioner for permission, before you repost something to e621?
How/when/where do you ask?
I usually send a note on Furaffinity, because I can do that directly from the post with an Xmonkey script, and because most artists are on FA.
And I have a spreadsheet where I keep track of everything :)
It's extra work, but it's better than using *only* the train wreck that is the notes system on FA.
Updated by Droqsle