Of course!
Yes indeed, pics get reposted all over the web. From places like Tumblr, Imagefap, xhamster, motherless, not to mention all the many amateur nudes sites.
You must always consider any photo you post will likely be saved and reposted. Adding a copyright or other warning does nothing to stop people grabbing you pics and posting them elsewhere. So unless you are happy for your pics to be spread all over the web, think twice before uploading them.
Once they are out there, you can't get them back.