A nameless gull

We took a nice walk on Lake Washington and spotted all of these gulls out on the pilings.  When I came home I spent forever trying to identify this little creature and never found a good match.  Perhaps a Franklin's gull?  Or young black-headed gull - there was one that had a completely black head. I'll post an extra photo that is a bit more of a closeup - maybe someone out there can name it.