I think it would be nice to have the option of adding a watermark to our preview images for downloads to ensure nobody viewing the project can easily make off with the uploaded pieces. I understand letting the client see everything they'll be getting, but it would also be nice if before they purchase a download, the previews could have a watermark added by the site that won't be on the actual download images.

So like, say you upload a pay-to-use line art people can color if they pay to download it. Instead of the previews of the image showing the full lineart with no watermark since that is what you'll be downloading, it shows the download images but with a big translucent watermark that could just say the site name or maybe could be changed to the artist's username.

This could, of course, be toggled off if people don't want it on their pieces, but I'd certainly like it because it might cut down on possible theft!

There could also be options similar to how toyhou.se does watermarks where it can be their generic site logo, or you could upload your own personal watermark to use on any of your stuff to make sure nobody's making off with anything for free without it being obvious!