If I visit a gallery for the first time, not all thumbs show up. If I refresh, there they are. I assume this is because there are a ton of images without thumbnails and the page times out before they all get generated.

Is there a .php script I can run at the command prompt to go through all the albums and generate thumbs? Right now what I have to do is go through every page of every album when I upload them, reloading some pages, to make sure all thumbs are there for visitors.

The cache manager plugin.

There's some reading on the subject:
http://www.zenphoto.org/news/why-are-some-of-my-thumbnails-sized-images-not-generated-why-does-zenphoto-make-my-server-crash-while-processing-images-

You can also activate the cacheManager plugin on the backend.
Please also read the info provided with the plugin.

CacheManager does not appear to do this, alas. Or rather, I should say it's no faster than doing it yourself.

The CacheManager plugin offers options to "purge cache" but there is no option to "generate cache" (aka thumbs).

In the album pages, I see a new option to "cache album images"...but that means going into each and every album. I added 40 new albums today, so that would be rather tedious.

Is there any way to checkmark a bunch of albums and say "cache album images"? Or to say "globally, cache all albums"?

"There's some reading on the subject:"

That link mentions an ImageMagick option under Option->Image. I'm running 1.4.3.2 and don't see it...?

Apparently you did not see the "cache images" button on the overview page. Not sure how you missed that.

As to ImageMagick, that will only appear if your server has the necessary software installed to support it.

"Not sure how you missed that."

Didn't think to look there :-) Thanks, that works great.

There is that old addage "When all else fails read the documentation." Each plugin has an Info button which loads up a document of how to use the plugin. In the case of the cache Manager it even lists the buttons the plugin provides.