By posting images to the site you are placing them under a Public Domain license. You will lose any copyright claim to the images and they will be free to be downloaded and shared. By nature of the license, this action is irrevocable and cannot be undone. Therefore images that you post will be permanently locked in and there is no way of removal.
For more information on public domain visit:
https://creativecommons.org/publicdomain/zero/1.0/
https://en.wikipedia.org/wiki/Public_domain