Hi,

can I change the theme option (Theme Colors) with a URL parameter, so I can develop a new one while displaying the current one to all ?

Erik

Not without modifying the zenphoto code. But what you can do is setup an unpublished album with its own theme. For that album/theme you can select a different Theme Colors.

Hmmm, is there a way to overload the CSS choice in the theme php if I am an admin then ?

Do you mean permanantly? If the theme supports it, yes. Do you mean while you are viewing the site? Then please re-read my previous post.

no, something more like a piece of code I could put on my theme to say:

if admin, they use this css instead of the basic one.

You can do this. The test you want is if(zp_loggedin()) {your css code} else {normal css code}