I am a new user of Zenphoto and I have found that the theme ZPBase is the closest to how I want my site to be displayed, but is it wise to continue using this theme, because it seems the author is no longer around?

We sadly have no resources to actively support and futher develop his themes. But we can at least try to help provide fixes to actual bugs if reported to us so they at least generally work with future Zenphoto versions. As we more or less try with all "unsupported" themes.

You can always try to create your own custom theme matching your requirments exactly or just take it over yourself.

Thanks, it's good to know that the zpbase theme is 'safe' for the time being.

I am now looking at the zenpage theme and will see what, with your help hopefully :), I can do with that one.