I am sorry to write aboit this issue but I do not find a soultion to it on my own.
According to the instructions on how to place images that are shown as thumbnails for videos into the album I did so. The thumbs are shown in the admin and in the latest view on the index but they are not shown in the album view ? I am very confused about that.

I already cleared the cache and the brwosers cache several times. No changes. I deleted the album and mad it new. No changes. Any idea someone.

Do you actually have the class video plugin and the jPlayer plugin enabled? Are the items published? Otherwise please post a link to the site.

This are the links with the video content / albums:

http://neu.aurora-sylt.de/videos/
and

http://neu.aurora-sylt.de/reportagen/

This is the index with the latest pics:

http://neu.aurora-sylt.de/

As one can see the thumbs in indexview are shown but not in the album itself.

Confused :/

Please try an official theme. If it works there, something is not right with your custom one.

It was working before. I transfered the videos from one album to another one. And after that the thumbs were gone ?

Actually the tumbs from images are shown see:
http://neu.aurora-sylt.de/welt/

Well, I have to admit that after checking with the standard templates it looks like there is a bug in the template. The thumbs are shown in the standard ones. This is strange :/ I am still confused.

Actually thumbs are created by the same standard functions. Somethinge the theme must do differently.

I found the error. By activating "class video" the "j-player" gets disabled. By activating "j-player" the "class-video" plugin will be disabled. Do you have any ideas ? The point is having only "class video" active the thumbs are shown on the album but the videos are not shown. Activating "j Player" the videos run but the thumbs get blacked out ?

The class video plugin actually is actually require for jPlayer or any other possible player to work.

The plugin does only disable itself if either the class video is not active or your using an external album folder (e.g. not in the webroot). On the latter no player works. And you cannot enable it naturally if already another player plugin is enabled.

None of them is true for my installation.

I am facing another problem. I wanted to install a third party player in the plugins folder in the root wich I did, but the plugins do not show up in the plugin list ?

Take a look please: http://www.zenphoto.org/news/using-plugins-and-third-party-features

Oh, right. I will try that immediately. Cheers. Soory by the way bothering around.

no luck at all. Not one of the third party players worked. I had tried: Flowplayer 5 / FLV Player / FLowplayer

then i tried to use jplayer again the result is online accessable at http://neu.aurora-sylt.de/videos/

Now that jplayer is active the thumbs are invisible on the album pages. By disabling the jPlayer the thumbs will be visible on the album pages. :/ still confused

If you tried the FLV player and flowplayer from our unsupported repository it is more or less expected for those not to work … For the Flowplayer5 I cannot tell.

Again the question: Does it work with official themes? If it does your theme is probably doing something wrong. Also make sure you use videos in formats and especially codecs supported. jPlayer has info about that on its website.

Also review error logs for possible errors (to remind that is Zenphoto logs but also server and browser logs). Otherwise we are just guessing.

I still have the issue that the thumbnails are invisible when jplayer is enabled. The funny thing about it is as I already mentioned that the thumbnails are shown in the latest.php even when jplayer is enabled. :/

I found Zenphoto a little while ago, looking for a replacement for the moribund Gallery package. I had some of the same problems as the original poster, so I took the time to write-up my solutions, at: http://thedance.net/~roth/TECHBLOG/zenphoto.html

@wcroth55:
Nice write up. Thanks for choosing Zenphoto ;-) However the install issues regarding permissions are really not usual. I can only say that I never had to deal with that sort of issues on any install I performed so far. And those are mostly standard shared hosting. Zenphoto should not have general 777 for any directories unless temporarily for writing.

Btw, modifying themes is not "hacking Zenphoto" ;-) Themes are always just a suggestion meant to be modifyied if anything doesn't fit personal requirements.

Interesting part about ffmeg which might be sadly out of question for probably most using shared hosting.