Re: login?
Claire,
I have made a site for a photographer client who has the same thing as what you are trying to achieve. I presume you want each of your clients to visit their own gallery using a password.
What you have to do is create not just one folder but a folder for each client.
So for example, you take photos for a couple called Anne and Ian
make a folder and call it 'annandian'
Password protect that with a username and password for that couple.
Then publish their gallery page to: public_html/annandian
Then when anyone trys to look at that page, only Ann and Ian can get in.
This is the way I set my client's up.
The other thing I did is not only give each folder a unique password, I also added the username 'admin' with the same password to each folder, that way, not only Ann and Ian can get in, but You can get in to each page using the same username and password and you wont have to keep looking them up all the time for each client gallery.
I also dont see why you need a log-out? Once the client has looked at their photos they will close the site down. Their cookies will allow them to relook at their gallery without logging back in unless they clear their cache.
Hope this helps.
How I did it.
Don't aim for success if you want it; just do what you love and believe in, and it will come naturally.