Originally Posted by Bladewire

Like tinyey.com?

You can do a Google reverse image search and go back to the first date posted.

You can drop the image into metapicz.com and see if there's a copyright in the exif data

Originally Posted by Busty2

Before 1978, in the United States, federal copyright was generally secured by the act of publication with notice of copyright or by registration of an unpublished work.

This has now been largely superseded by international conventions, principally the Berne Convention, which provide rights harmonized at an international level without a requirement for national registration. However, the U.S. still provides legal advantages for registering works of U.S. origin.

? now lasts 75 years from production of works or image.