It is not necessary for Ben to make a statement of ownership.  As the
creator of the images, they are his property, and if someone wishes to
make use of them, they are required, by US copyright law, to ask his
permission.

Since they are not marked as copyrighted, enforcement becomes an
issue, but legally, they are his.

Also, crossing the US/Canadian border could muddy things up a bit.

Karl Wolz