Thank you all for your comments yesterday. A lot of you mentioned watermarking my caps and I have considered it, but here's why I don't want to take that step.
- It's more work and making and sharing these caps is time-consuming enough as it is.
- I'd have to put the watermark in the middle of the caps somewhere since this person is re-posting them on Instagram, which crops everything square.
- Watermarking the caps really limits what they can be used for and would be an annoyance for anyone who wanted to use the for fanart or icons.
Mostly it just feels like a drastic step for all the above reasons just due to one bad apple in the fandom who doesn't believe in crediting anyone. Though in all fairness, they re-posted one of my on-set photos (that are watermarked) from 13x03 and they not only kept the watermark, but credited me in the post. So it was basically double-crediting me. But somehow they can't credit my SPN caps. *shrugs* Very weird.
Anyway, you win some battles and lose others. Thankfully, most of the fandom are pretty good about giving credit. It's just a matter of dealing with or accepting the few bad eggs out there that don't.