Public domain photos only?

I am new here do I understand this correctly. Nothing that is copyrighted cane be uploaded?
This kills the site for me, I am an artist, surly there is an exception if I am the copyright holder or does any picture posted belong to everyone and void my copyrights. What gives them the right to do that? Please clarify.

No nudity, porn or inappropriate images. Upload public domain images only. Jpg, png or gif images can be uploaded. Upload the highest quality images possible.

I have never seen it worded like this before, The rights are on loan to contest sites on the internet I am already under a terms of use with them, I need to know that I am safe to show work here.

I am assuming I am being paranoid, just that we are clear these are not for use ok. Moving on then, Hello Listal.

It's perfectly fine to upload your own artwork, no problem.