I want to try a nightly build but would like to retain my existing setup and albums.
Are there certain files I should leave alone?

You need to setup a new separate installation.

More to the point. The nightly build installs just the same as the releases. So, you can install over an existing site--it is best to delete the old zenphoto files first. But you leave your albums intact.

Or, as acrylian suggests, you can try an experimental install by installing in a different folder. Then you would also have to add albums and images to the experimental install.

Thank you for the info.
I will try the experimental install 1st, then if I am satisfied with the experimental install and like the recent nightly build better, I will try the install-over method.

Jim Trageser