Ideas
-1
Declined
DNP option for submissions
Giving an author the option of placing an indicator/reminder on the page of a submission that it should not be reposted on e621.net and similar sites would be a nice feature. This could be extended to compare file hashes and eventually visual similarity.
Customer support service by UserEcho
While i think this is a good idea, i really dont see how you would be able to enforce this from FN out.
This doesn't seem like something that FN can patrol or control.
Also, with the current existence of descriptions, tags and you being able to add watermarks to your work it doesn't really seem necessary.
To be honest though I've never really understood the issue with reposting anyway, just make sure to include your name CLEARLY on your art [not just a signature that many won't be able to read] and maybe even a link to your gallery [you could always add a border around your pieces like a frame and place the info there.]
Yes, you don't have a say in where your art is being posted, which sucks, but at least it's free advertising if you do your part.
At this point, it's likely best to put a DNP notice in your description if you don't wish for the image to be posted elsewhere.The specifics can really vary from user to user, so having custom text for your own work would show what you're okay and not okay with.