YES!
All assets on this website (https://pddatabase.github.io/*) or in the GitHub repositories (PDDatabase/PDImages, ...) are either licensed under CC0 Public Domain or are Public Domain.
CC0 Public Domain is a license that removes all copyright from an asset, allowing anyone to use it for anything they want, effectively putting it into the public domain.
Public Domain is not a license. Public Domain is what works are classified as after their copyright expires, which allows them to be used by anyone for any reason.
Cornell Edu. on Public Domain | CC Public Domain Mark
If everything is public domain, then why in the bottom left does it say "All Rights Reserved."
All assets on this website are public domain; however, the website code, styling, and mechanics are not public domain and do not have a license, which means this website cannot be copied, distributed, or modified for any other use.