Most sites will have some privacy options, with varying degrees of control/permissions to achieve what you're looking for.
E.g. With facebook and google+, you can choose to share images right down to specific people, or have private links to non-public albums. With 500px, it's either private or public. Photobucket is one of the free services I'm aware of that has password-protected albums, there may be others I don't know about. With Flickr, you can generate a guest pass to share private images/albums with specific people:
https://www.flickr.com/help/sharing/#2184