Minecraft is copyright Mojang AB and is not affiliated in any way with this MCSkinSearch.
Feel free to add your own account by searching your minecraft username. However, it may have be already added by someone you know.
No, if you have a problem with this you are going to have to take it up with Mojang legal.
No, this is not a skin upload site. The only way for you to have your skin appear on this website is to have a premium Minecraft account with a custom skin.
I am the creator and developer of this site.