One thing you need to understand about CSS in flash(Imagevue), is that it only affects text styles and formatting. CSS in flash does not (and can not) have any effect on the actual layout, or background color. Use CSS stylesheet only to change the various TEXT-formatting in Imagevue!
Regarding your specific questions:
52357255 wrote:a css at my theme
As mentioned, CSS is only for full control of the formatting/styles. It has no impact whatsoever over the layout in Imagevue.
52357255 wrote:I see a themeconfig.xml at my theme. I see there "<horizontal_margin type="integer" ". When I change this then nothing is happening.
You should not be editing XML files manually. TYou may have been viewing the default template file, but this may be overwritten by specific theme settings stored elsewhere. To correctly change your theme config, go to your theme config in the admin: admin -> themes -> edit your theme ...
52357255 wrote:How can change the width of my menu items
This I answered here:
viewtopic.php?f=33&t=6504
52357255 wrote:I see a css directory with css files But has this anything to do with my theme?
As mentioned, I don't recommend you use file browser to change any settings, as you can do all this from the admin. The CSS directory you were looking at, was mostly likely some default CSS simply for the admin and the HTML container for the Imagevue gallery. The CSS files for the themes, are located within the specific themes folders.
52357255 wrote:At the opening of the gallery there is a kind of curtain moving over the start picture. How can I disable this?
This is your "startfolder", which is defined in your main settings. You can go to admin -> manage -> "start" folder ... You can change the TYPE of this gallery(from the panel on the right), or you can delete it. You would then have to go to settings and define a different startfolder.
In essence, this is just a folder, set up to be a "filemod" so it displays the photoblinds instead of acting as a normal gallery. More info:
https://www.photo.gallery/documentation/filemod/
52357255 wrote:I see in the documentation at the admin it should be possible to 'use', 'create new', 'try'. It should be possible to 'edit' and to 'delete' a theme as well. But I don't see these two last menu items!!??
You mean for themes overview? This is a bit obscure in the latest release, because we made it so that you can't edit or delete default themes (so upgrading goes easier). Instead, find the theme you want to use, click "create new" from this theme, and then you can edit your new theme.
52357255 wrote:I mean what are the important css file's to mod my theme.
As mentioned, CSS is only for editing the actual TEXT FORMATTING in the gallery. More info on the CSS stylesheets here:
https://www.photo.gallery/documentation/cssreference/
52357255 wrote:I have read that is not possible to change or it is not supported to move the horizontal menu. But I have seen gallery's where the menu is in the middle!
Generally speaking, the horizontal_menu is a bit weak, and you can't do much with it. We hope to provide a dedicated horizontal menu in a future release. The galleries you have seen, may have included their own menu as part of the SWF background image.