When an so-called shared-album is created on Photos, this album is not visible in the Archive, so probably it is impossible to insert some pictures here:
But that is not true as you can see above.
However: if a shared person adds some pictures of its own, these are not shown and can not be added to this blog.
A few days later I did remove the shared album from my Photos and you see: the links are broken. So Blogger does not generate backupcopies in the special Blogger-album, but assumes that your albums will be there for eternity.