No problem. I've split your post into a new thread.
The 'Post new topic' link is just above the second blue bar at the right-hand side of the page (once you've selected the 'Juicebox-Pro Support' or 'Juicebox-Lite Support' forum).

(1) On Showkase's 'Pages' tab, click 'New Page', create a Gallery Index Page and click 'Save'.
(2) Now, still on the 'Pages' tab, just drag and drop your Juicebox Gallery Pages (drag and drop the page names in the tree on the left hand side) onto the Gallery Index Page (in the order you want their thumbnails to be displayed).
(3) Click 'Save' and 'Publish'.

Each Juicebox Gallery Page listed under the Gallery Index Page will be represented by a thumbnail image.
By default, the thumbnail image will be the first image in the gallery. If you like, you can change this to be any other image from the gallery by editing the Juicebox Gallery Page, going to the 'Images' tab and selecting a new image in the 'Index' column. Be sure to republish your site after making this change.

Incidentally, I notice that you have a large logo that is taking up a little more that the regular header height and is pushing your Juicebox galleries down their respective pages.
You can compensate for this by going to 'Site -> Customize Theme -> Gallery Pages' and entering a negative pixel value (e.g. "-100") in the 'External fit px' input field.
This will reduce the height of each gallery by the amount you enter and all your galleries will be able to be seen in full (without the need for vertical scrolling) regardless of the height of the user's browser window.

I hope this helps.

Are you referring to a folder that you are trying to save the gallery to (or a folder that a source image is in)?
What error are you getting?

You should be able to use the ø character in a gallery (although it might not be wise to do so).

As a test, I've just successfully created a gallery with JuiceboxBuilder-Pro v1.5.0 (on a Windows 10 PC) using an image with a ø character in its filename (from a folder with a ø character in its name) and saving the gallery to a new folder with a ø character in its name. The gallery is saved correctly, uploads to my web server correctly (via Filezilla), displays correctly and the the ø character also appears in the image caption correctly.

However, as image filenames and gallery folder names form parts of URLs when uploaded to a web server, it would be safer to use only web-safe characters. Please see section 2.3 of this document for details: https://tools.ietf.org/html/rfc3986#section-2.3

You should have no problems (with JuiceboxBuilder-Pro, your web server, FTP software or browsers) when using any or all of these unreserved characters.

I'd stick with web-safe characters for file and folder names and keep accented and special characters for image titles and captions.

I notice that your gallery has a height of 88%. I think it would be difficult to get a clean working solution (with either CSS or JavaScript) using such a gallery height. The suggestions below use a gallery height of 100% so that the gallery fills its container and when JavaScript is used to determine the height of the container, you know that the gallery is the same height.

Take a look at the Using a Resizable Gallery with a Header support section.
The View Resizable Gallery with Top Menu Example has a header and a footer (both with fixed heights) and the gallery takes up the remainder of the available space (no matter what size the browser window is) without any scrollbars.
You can view the source of the web page in your browser and copy/modify the code to suit your own needs (removing the footer, changing the header content and swapping the sample gallery with your own).
The example also switches between galleries (something you might not need) and uses an external CSS file.
Here is a single file solution that you might like to use. (The code should be fairly easy to follow.)
To see it in action, create a sample gallery with JuiceboxBuilder-Pro (just use all default settings) and use the following code as the gallery's 'index.html' file.

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8" />
        <style type="text/css">
            html, body {
                height: 100%;
                overflow: hidden;
            }
            body {
                background-color: #222222;
                margin: 0px;
            }
            #header {
                background-color: #222222;
                color: #666666;
                font-family: sans-serif;
                font-size: 20px;
                height: 50px;
                padding: 10px 0px;
                text-align: center;
                width: 100%;
            }
            #wrap {
                width: 100%;
            }
        </style>
        <script type="text/javascript" src="jbcore/juicebox.js"></script>
        <script type="text/javascript">
            var jb;
            function doLayout() {
                var windowHeight = parseInt(window.innerHeight ? window.innerHeight : $(window).height());
                var headerHeight = parseInt($('#header').outerHeight(true));
                var galleryHeight = windowHeight - headerHeight;
                $('#wrap').height(galleryHeight);
                if (jb) {
                    var galleryWidth = parseInt($('#wrap').innerWidth());
                    jb.setGallerySize(galleryWidth, galleryHeight);
                }
            }
            $(document).ready(function() {
                doLayout();
                $(window).resize(doLayout);
                jb = new juicebox({
                    containerId: "juicebox-container"
                });
            });
        </script>
        <title>Test</title>
    </head>
    <body>
        <div id="header">
            <span>Header</span>
        </div>
        <div id="wrap">
            <div id="juicebox-container"></div>
        </div>
    </body>
</html>

You're welcome!
I'm glad you've got it working.
Thank you for letting me know.

By default (using the regular embedding code), Juicebox will look for a file named 'config.xml' in the same directory as the page containing the gallery's embedding code. (Your gallery structure does not have a 'config.xml' file in this location.)

If you move or rename this file, then you can point towards it using a configUrl option in your embedding code.
When using a configUrl, all paths in the 'config.xml' file will still be relative to the embedding code page.

As you have uploaded an entire Juicebox gallery (your 'Juicebox' folder) to your web server, you can point towards this folder using a baseUrl option. Please see here for details.
When using a baseUrl, all paths in the 'config.xml' file will be relative to the baseUrl so there is no need to make any modifications to any gallery files.

Just change your gallery's embedding code to the following (add the baseUrl entry pointing towards the gallery folder) and all should be well.

<!--START JUICEBOX EMBED-->
<script src="/Juicebox/jbcore/juicebox.js"></script>
<script>
    new juicebox({
        baseUrl: "/Juicebox/",
        containerId: "juicebox-container",
        galleryWidth: "100%",
        galleryHeight: "100%",
        backgroundColor: "#222222"
    });
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

Short descriptions of configUrl and baseUrl can be found in the Embed Options section of the Config Options page.

Please check your email. I have sent you a message.
Once I am able to see your gallery, I should hopefully be able to help further.
Thank you.

This web page also has the code:

<head><link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css">

... before the Doctype Declaration:

<!DOCTYPE html>

... (and two opening <head> tags).

I have not been able to exactly replicate your problem but when I remove the Doctype Declaration from a test gallery page of my own, the gallery does not expand correctly (when useFulscreenExpand="TRUE") so it certainly looks like the incorrect location of the Doctype Declaration on your own page may be the cause of your problem.

Please post the URL to your gallery's web page so that I can take a look at the problem for myself.
Once I am able to see the problem live on your web server, I should hopefully be able to determine the cause of the problem and propose a solution.
Thank you.

In the meantime, please check that:
(1) You are using the latest version of Juicebox-Pro (v.1.5.0) to ensure that any bugs from previous versions are not contributing to your problem. If necessary, please see the Upgrading Juicebox support page.
(2) You have uploaded the complete 'jbcore' folder (including the 'full.html' file) to your web server.
(3) The permissions of all the gallery files and folders on your web server are not too restrictive. Default permissions of 644 for files and 755 for folders should be fine. You should be able to check and change permissions using an FTP program such as Filezilla or via your web hosting account's online file manager.

That's really strange. I don't think I've ever heard of anyone being able to use the Open Gallery button but not the New Gallery button. I'm really not sure what could be causing your problem.
Maybe there is an issue with the functionality of just the button on your system. Try going to 'Gallery -> New...' from the drop down menu at the top or use the keyboard shortcut 'Ctrl+N'. These are alternate ways to start generating a new gallery.

If the Open Button seems to be working, then you should hopefully be able to open the sample 'web' gallery from the Juicebox-Pro zip file.

The 'web' gallery is a sample gallery with all default settings that you can hopefully use as a template to start creating your own gallery. (Just delete the two sample images and add your own on the 'Images' tab, customize the gallery with the available configuration options on the 'Customize' tab and save the gallery on the 'Publish' tab.)

Unzip the 'juicebox_pro_1.5.0.zip' file and you will find the 'web' gallery in the 'juicebox_pro_1.5.0/web/' location.
This is the folder that you should navigate to and select after clicking the Open Gallery button.

You've welcome!
I've glad you've been able to resolve your problem.

First of all, try fixing the HTML errors on your web page. HTML errors can cause problems when web pages are rendered and some browsers can be more tolerant towards errors than others.
Your web page starts with the following code:

<head><link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css"><!DOCTYPE html>
<!-- jsn_boot_pro 3.0.2 -->
<html lang="de-de" dir="ltr">
<head>

The Doctype Declaration (<!DOCTYPE html>) should be at the very top of the document (before anything else) and there should be only one opening <head> tag.
Try changing the code above for:

<!DOCTYPE html>
<html lang="de-de" dir="ltr">
<head>
<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css">

Next, check your web page for any other HTML errors using the W3C Markup Validation Service and fix any errors reported.
Once the code on your web page validates correctly, your web page should be rendered with greater predictability and consistency across different browsers.

Hopefully this will help. If not, then the problem may be due to custom CSS on your page conflicting with the gallery's own CSS. If this is the case, then it might help to expand the gallery on a page of its own (where it will not be affected by any custom CSS) by setting expandInNewPage="TRUE" (in JuiceboxBuilder-Pro's 'Customize -> General' section).

Yes. Please see the Embedding Multiple Galleries support section for details on embedding multiple galleries on separate HTML pages or on one HTML page. (Each gallery can have a unique layout.)

You would just need to embed a gallery into a web page as normal (following the instructions here) and overlay whatever content you like on top of the gallery using CSS (to position the custom content and stack it on top of the gallery using a high enough z-index).
Please note that Juicebox was not designed with this in mind so you might run into problems that need to be tackled as you encounter them.
However, something like the following might work. To see it in action, create a sample gallery with JuiceboxBuilder-Pro (just add a few images, don't worry about the configuration options) and use the following as the gallery's 'index.html' file.

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Juicebox-Pro Gallery</title>
    <meta charset="utf-8" />
    <meta name="viewport" id="jb-viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1, maximum-scale=1, user-scalable=0" />
    <style type="text/css">
    body {
        margin: 0px;
    }
    #wrap {
        position: relative;
    }
    #juicebox-container {
        position: absolute;
        top: 10px;
        left: 10px;
    }
    #overlay {
        position: absolute;
        top: 10px;
        left: 10px;
        width: 600px;
        height: 400px;
        z-index: 9999;
        color: #ff0000;
    }
    </style>
</head>
<body>
    <!--START JUICEBOX EMBED-->
    <script src="jbcore/juicebox.js"></script>
    <script>
    new juicebox({
        containerId: 'juicebox-container',
        galleryWidth: '600',
        galleryHeight: '400',
        autoPlayOnLoad: 'TRUE',
        buttonBarPosition: 'NONE',
        enableLooping: 'TRUE',
        screenMode: 'LARGE',
        showAutoPlayStatus: 'FALSE',
        showImageNav: 'NEVER',
        showImageOverlay: 'NEVER',
        showThumbsOnLoad: 'FALSE'
    });
    </script>
    <div id="wrap">
        <div id="juicebox-container"></div>
        <div id="overlay">Custom content goes here.</div>
    </div>
    <!--END JUICEBOX EMBED-->
</body>
</html>