"To be honest, if you want to be 100% safe, the only thing you can do is not post them."

Absolutely true!!!  I have on several occasions suggested to Renderosity that they implement some form of watermarking to make image theft a bit more difficult....so far, it hasn't met with positive response around here.  In the mean time, Rendo is like a freebie shopping mart for image thieves!!!.

So, really you only have a few options;

1)Watermark anything you post.

2)Post very small versions of your images.

3)Don't post anything.

Having had some of my images stolen already....I now post less, post smaller....and anything that really may be worth selling doesn't get posted here.

 

In youth, we learn....with age, we understand.