First of all, please try clearing your browser's cache and trying again.
This will ensure that your browser fetches and uses the most recent versions of the WP-Juicebox files from your web server.

If this does not help, then please try temporarily disabling all plugins other than WP-Juicebox to see if this helps. It it does, then re-enable your plugins one by one (checking the WP-Juicebox functionality after each one) until you find the source of the conflict.

If you use the BulletProof Security plugin, then this may be the cause of your problem and you will need to add a skip/bypass rule to the .htaccess file in your root directory as follows:

# Juicebox skip/bypass rule
RewriteCond %{REQUEST_URI} ^/wp-content/plugins/wp-juicebox/ [NC]
RewriteRule . - [S=13]

If you do not use the BulletProof Security plugin, then please check your .htaccess file for an entry such as:

<Files *.php>
    deny from all
</Files>

If you find such an entry, either comment it out or remove it and WP-Juicebox should work as expected.

Thank you for your suggestion.

In order to ensure that ideas for future versions are not overlooked by the developers, I would encourage you to post in the Feature Requests thread. Thank you.

That's good to hear. I do not know what might have been causing the temporary glitch but I am glad that everything seems to be working OK at the moment.

Juicebox was not designed with this in mind (the ability to run some custom JavaScript code or to redirect to a new URL on clicking a thumbnail).

If it is possible to find a CSS selector (a class or id) for the thumbnails within Juicebox which you could attach a jQuery click handler to, then you could perhaps run some JavaScript code using the Juicebox-Pro API to get the index of the image currently being displayed when the element is clicked (and then act on the image index accordingly).

The code might look something like this:

<script>
    var jb = new juicebox({
        backgroundColor: '#222222',
        changeImageOnHover: 'TRUE',
        containerId: 'juicebox-container',
        galleryHeight: '400',
        galleryWidth: '600'
    });
    jb.onInitComplete = function() {
        $('CSS_SELECTOR').click(function() {
            var currentImage = jb.getImageIndex();
            switch (currentImage) {
                case 1:
                    window.location.href = 'http://www.example.com/';
                    break;
                case 2:
                    window.location.href = 'http://www.google.com/';
                    break;
                default:
                    window.location.href = 'http://www.juicebox.net/';
                    break;
            }
        });
    };
</script>
<div id="juicebox-container"></div>

Unfortunately, I have not yet found a CSS selector which works. This may be due to Juicebox having its own click hander on the thumbnails so it may not be possible but it might be worth investigating further. I hope this at least points you in the right direction.

It sounds like you may be clicking 'Insert into post'. This is not necessary (and will include the images in the post outside the gallery). All that is required to include images in a WP-Juicebox gallery is to attach them to the post. Just drag and drop your images into the media window and after they have completed uploading, just close the media window using the cross in the upper-right corner.

Unfortunately, there is currently a known bug whereby elements which have explicitly been assigned a CSS 'position' are not covered by the fullscreen gallery (they should be). This bug should hopefully be fixed in the next version of Juicebox.
In the meantime, there are a couple of workarounds:

(1) Set useFullscreenExpand="TRUE" (in the WP-Juicebox gallery settings interface section).
... or:
(2) Set expandInNewPage="TRUE" in (in the Pro Options text area in your gallery settings window). When the gallery is expanded, it will be displayed on a page of its own rather than on top of the embedding page. Please note that this option is available in Juicebox-Pro only (and not in Juicebox-Lite).

Yes. Set enableDirectLinks="TRUE" (in JuiceboxBuilder-Pro's 'Customize -> General' section) and you can have a unique URL for each image in your gallery.
For example, a URL to go directly to the 7th image in a gallery would look something like: http://www.example.com/gallery/#7
Please see the description of the enableDirectLinks configuration option in the General section of the Config Options page for a little more detail.

@Mikael P.

I understand your request for a quick and easy way to select a number of images. (Thank you for the suggestion.)
However, if you are familiar with HTML, JavaScript and PHP, you could perhaps achieve this functionality already using the Juicebox-Pro API and PHP session variables.
You could create a link (either within your gallery or elsewhere on your web page) to 'Add an image' to a selection list.
When clicked, the link would get the current image number (using the getImageIndex() API method) and pass it onto a PHP script which would add the image number to a PHP session variable array.
You could have further links (and separate corresponding PHP scripts) to display the current list of selected images to the user, reset the list and email the list to yourself.
As noted, knowledge of HTML, JavaScript and PHP would be necessary but it is possible (although it might turn out to be a rather complex project, especially if you wanted to extend the functionality by allowing the user to send you notes).

Your audio plays fine in your gallery in IE11 so your gallery's audioUrlMp3 configuration option is set OK.
As noted in the Adding Audio support section:

If you are using IE9 or later and still do not hear your audio track, then try clearing your browser's cache before reloading your gallery's web page to ensure that your browser is fetching and using the latest versions of your gallery files.

I do not see this when viewing your sample post's web page in Mobile Safari on an iPod Touch.
The gallery's Splash Page displays as expected and the gallery displays and functions fine when the Splash Page is tapped.
Try clearing your browser's cache before reloading your gallery's web page to see if this helps.
Otherwise, please let me know what device and browser you see the problem in and, if possible, please upload a screenshot somewhere (and provide a link) so that I can see what you are seeing.

Juicebox uses only one set of configurations for both Small and Large Screen Modes.
You can disable the Sharing Buttons by setting the Sharing Options to FALSE but this will disable in all browsers and on all devices.
A single tap on a mobile device's screen will hide the overlay (until tapped again) to clear the screen of all overlay components (Back Button, Button Bar, caption area).

If you create a gallery with JuiceboxBuilder-Pro, you can open the gallery's XML file in a plain text editor, copy the configuration options (the attributes to the opening <juiceboxgallery> tag) and paste them into the Pro Options text area of a WP-Juicebox gallery's settings window.
Please make sure that each configuration option is entered on a line of its own.
Also, please note that any Lite configuration options entered into the Pro Options text area will automatically be filtered out and the Lite values from the plugin's interface will be used instead.

It looks like you are using WP-Juicebox v1.4.2.0 and your images are sourced by NextGEN Gallery.
Please try upgrading to the latest version of WP-Juicebox (v1.4.2.1) which can be downloaded from the plugin's support page here.
Changes were made between v1.4.2.0 and v1.4.2.1 which should hopefully significantly speed up the loading of your NextGEN Gallery images.
You will not need to modify any of your galleries but you will need to ensure that you upgrade the Lite 'jbcore' folder within the plugin's files with your own 'Pro' version. (Instructions for upgrading WP-Juicebox to Juicebox-Pro can also be found on the plugin's support page.)
I do not know if this will solve the problem you report on expanding the gallery but you might like to try setting imagePreloading="NEXT" (in the Pro Options settings window) so that the browser preloads only one image at a time. (The default setting for imagePreloading is PAGE and this preloads all images on the current thumbnail page.)

When JuiceboxBuilder-Pro resizes images, it strips all metadata (EXIF, IPTC, ICC Profiles). If you need to retain metadata in your gallery's images, then the only option is to deselect the 'Resize Images' checkbox and allow JuiceboxBuilder-Pro to copy your original images across to the gallery's 'images' folder.
If you plan to use multi-size images and want to retain metadata, then you will need to create your own sets of images (in an imaging program such as Adobe Photoshop) and replace the ones generated by JuiceboxBuilder-Pro. If you are just creating one or two multi-size image galleries, this might be a possible workaround. As long as you allow JuiceboxBuilder-Pro to create multi-size images (and then replace them with your own images with the same filenames after the gallery has been created), then the smallImageURL and largeImageURL entries will be in place in the gallery's XML file and the functionality will still be there in the gallery.

Try increasing the quality of the images from the default value of 80 to something higher to see if this helps.

If you want more control over the images in your gallery than JuiceboxBuilder-Pro can provide, then you will have to create your images elsewhere and copy them into your gallery folder.

However, please post any suggestions you may have in the Feature Requests thread.
I cannot promise that your suggestions will be incorporated into future versions of Juicebox but it is certainly the best place to post ideas such as these.

It looks like the emulator website you are using may not be giving a true representation of your web pages in the selected devices.
Are you using their Basic or Advanced emulation?
According to their own website, "Advanced emulation allows you to see your websites
like they are rendered in mobile devices.". This suggests that their Basic emulation does not.
It looks like all their Basic emulation is doing is resizing the gallery to the selected device's screen size. However, because this is all it is doing, Juicebox is not detecting the selected device or its actual browser window size so it is not switching to Small Screen Mode (and the gallery is always being displayed in Large Screen Mode).
Try using their Advanced emulation or, if you are already doing so, try a different emulator such as Manymo which may give more accurate results.

I have viewed your gallery on an iOS device and also do not see thumbnails so it looks like your gallery is working as expected (just not in your chosen emulator website).

It looks like the problem may be your iframe's fixed height of 900px. You may need to reduce this in order for your gallery to take up less height on your web page in mobile devices.
Also, your iframe has a height="900px" attribute. This should be just height="900" (although I would recommend that you try reducing the value). The 'px' suffix should be used only if setting the height via CSS.