You're welcome!
It's an unfortunate turn of events but, thankfully, not an insurmountable problem.

Unfortunately, Firefox 68.0 (released yesterday, 9 July 2019) has introduced a new security restriction which blocks the loading of Juicebox galleries locally (from your computer's hard drive). (There is no problem once the gallery has been uploaded to a web server.)

Here is the relevant entry from the Firefox 68.0 Release Notes: https://www.mozilla.org/en-US/firefox/6 … easenotes/

Here are the steps required to relax this security restriction:
(1) Enter about:config in your Firefox browser's address bar.
(2) Click past the warning via the "I accept the risk!" button.
(3) Enter privacy.file_unique_origin in the search bar.
(4) Double-click the Preference Name to change the Value from 'true' to 'false'.

***Please do so at your own risk*** (although it should be no more of a risk than running the previous version of Firefox (67.0.4)).

I hope this helps.

You're welcome!
I hope my notes help. (I realise that there is a lot to consider!)

There's no automated way to ensure that an automated slide show matches the length of an audio track but you can adjust the length of time an image is displayed for (before transitioning to the next one) via the displayTime configuration option (in JuiceboxBuilder-Pro's 'Customize -> AutoPlay' section) and the time it takes for one image to transition to another via the imageTransitionTime option ('Customize -> Main Image').
You should hopefully be able to change the length of time your slideshow plays for with these options.

Here are a couple of tips for anyone looking to do this...

(1) Just in case your slideshow time does not exactly match the length of the audio track, you might like to enable audio looping (so that the audio track starts again after finishing) by setting loopAudio="TRUE" ('Customize -> Audio').

(2) If you want to prevent the user from interrupting the flow of the slideshow (for example, by manual navigation to an image) or pausing the audio track (which would break the synchronization of the AutoPlay and Audio), then you will need to:

• Set AutoPlay and Audio to start on load: autoPlayOnLoad="TRUE", playAudioOnLoad="TRUE"

• Disable keyboard controls: enableKeyboardControls: "FALSE"

• Hide AutoPlay, Audio and navigation buttons from the Button Bar: showAudioButton="FALSE", showAutoPlayButton="FALSE", showImageNav="NEVER", showNavButtons="FALSE" (or just hide the entire Button Bar by setting buttonBarPosition="NONE")

• Prevent thumbnails from being displayed: showThumbsButton="FALSE", showThumbsOnLoad="FALSE"

• Disable image click functionality: imageClickMode="NONE"

Important Note:
Unfortunately, very recently, desktop browsers have started to block the autoplay of audio (and video).
Firefox, from version 66 onwards, now blocks the autoplay of audio (and a click is required from the user to start the audio).
Likewise, recent versions of Chrome, Opera and Safari also now block the autoplay of audio.
playAudioOnLoad continues to work only in Edge and Internet Explorer 11.

Here are the release notes for Firefox 66 where this change of behavior was first noted: https://www.mozilla.org/en-US/firefox/6 … easenotes/

I have contacted the developers to let them know of this and a note regarding this change should be added to our online support documentation in the next website refresh.

Unfortunately, there is nothing that can be done from within Juicebox to override this new browser functionality.
If a user want to allow the autoplay of audio in a browser, then the browser's settings need to be changed by the user.
Please see this web page for more information regarding Chrome, Firefox and Safari.
Chrome: https://developers.google.com/web/updat … cy-changes
Firefox: https://support.mozilla.org/en-US/kb/block-autoplay
Safari: https://webkit.org/blog/7734/auto-play- … for-macos/

As unfortunate as it is, there is nothing that can be done from within Juicebox to force audio to autoplay in modern browsers any more.

That's great! Thank you for letting me know.

I don't have an iPhone but I have an iPod Touch 6 running iOS 12.3.1.
If you like, let me know the URL of the web page you'd like me to check and I can post a screenshot in this thread to let you see what I see in Mobile Safari.

If you'd like your Audio Button to stand out from the other icons on the Button Bar, you could color it differently by using CSS such as the following. (This example will color the Audio Button red.)

.jb-bb-button.jb-bb-btn-audio {
    color: #ff0000;
}

Put this CSS code at the foot of your gallery's 'jbcore/classic/theme.css' file. (If you put the code in the gallery's embedding page, then the Audio Button will not be colored if/when the gallery is expanded in a new page (for example, on iOS devices).)

This might at least attract some attention and users will hover over the button where they will then see the rollover tooltip text  "Play Audio". If you like, you can change this tooltip text via the languageList configuration option. Please see the International Gallery Text support section for details. (The languageList option was intended for translating the on-screen text into different languages but you can use it to change the messages to whatever you like.)

If you want to actually change the Audio Button icon itself, then this is also possible (but more difficult).
Please check out the Using Custom Icons support section in the Theming Guide for details.

Alternatively, you could create your own Audio Button and place it alongside the gallery on the embedding page.
You would need to use the Juicebox-Pro API (specifically the toggleAudio() method) and knowledge of JavaScript would be required.
Take a look at the Juicebox-Pro API demo gallery here. You'll see that there is a 'Toggle Audio' button to the left of the gallery. You could do something similar for your own gallery's web page. (Check out the source of the demo in your browser to see how it is done.)
Your custom Audio Button does not need to be an HTML button, though. You could make any HTML element (e.g. text or an image) clickable and act like a button.

I hope this gives you some ideas as to how you could make your Audio Button more prominent now that autoplay is becoming less likely to happen (depending on the user's browser).

That's great!
I'm glad you've got it working.

This is not something that Juicebox was designed to do but it should be possible with help from the Juicebox-Pro API.

You'll need to edit your gallery's embedding code, though.
There are no configuration options which you can set to make this happen.

If you want to redirect the user to a custom web page when the last image in the gallery has been reached, then try something like this:

<script type="text/javascript">
    var jb = new juicebox({
        backgroundColor: "rgba(0,0,0,1)",
        containerId: "juicebox-container",
        galleryHeight: "100%",
        galleryWidth: "100%"
    });
    jb.onInitComplete = function() {
        var imageCount = jb.getImageCount();
        jb.onImageChange = function(e) {
            if (e.id === imageCount) {
                window.location.href = 'http://www.example.com';
            }
        };
    };
</script>

If you want to introduce a delay (so that the last image can be seen for a set amount of time before the redirection happens), then try the following, changing the delay time of 5s (500ms) to whatever you like:

<script type="text/javascript">
    var jb = new juicebox({
        backgroundColor: "rgba(0,0,0,1)",
        containerId: "juicebox-container",
        galleryHeight: "100%",
        galleryWidth: "100%"
    });
    jb.onInitComplete = function() {
        var imageCount = jb.getImageCount();
        jb.onImageChange = function(e) {
            if (e.id === imageCount) {
                window.setTimeout(function() {
                    window.location.href = 'http://www.example.com';
                }, 5000);
            }
        };
    };
</script>

If you want the redirection to happen only when the last image has been reached via AutoPlay (and not by user navigation), then try the following, which also includes the delay:

<script type="text/javascript">
    var jb = new juicebox({
        backgroundColor: "rgba(0,0,0,1)",
        containerId: "juicebox-container",
        galleryHeight: "100%",
        galleryWidth: "100%"
    });
    jb.onInitComplete = function() {
        var imageCount = jb.getImageCount();
        jb.onImageChange = function(e) {
            if (e.id === imageCount && $('.jb-bb-btn-auto-play').first().hasClass('jb-status-playing')) {
                window.setTimeout(function() {
                    window.location.href = 'http://www.example.com';
                }, 5000);
            }
        };
    };
</script>

I hope this helps and points you in the right direction.

In order for both JuiceboxBuilder-Pro and the Juicebox Plugin for Lightroom to generate an absolute path for the og:image entry, it is necessary to complete the Share URLcorrectly (in both applications).
Both applications generate an absolute path by concatenating the Share URL and the path to the first image in the gallery.
The only difference between JuiceboxBuilder-Pro and the Juicebox Plugin for Lightroom in this respect is that, in JuiceboxBuilder-Pro, the og:image entry is left empty if the Share URL is empty whereas the Juicebox Plugin for Lightroom still outputs the path to the first image even if the Share URL is empty.
The end result is the same in both cases, though: the Share URL must be completed correctly (in both applications) for the Facebook share window to display the image.

That is correct. This is just how Facebook works (by using the web page's Open Graph og:image entry for all shared links on the page).
It is not possible (at least not easily) to have the shared image's thumbnail displayed in the pop-up Facebook share window due to limitations imposed by Facebook on what data can be passed via their share URL. Only one thumbnail image can be used per web page. However, the shared link itself will still point towards the correct image within your gallery.

You can think of the og:image as being representative of the gallery as a whole so you could use an image which best represents your gallery.
The og:image does not need to be an image from the gallery itself. You can edit the gallery's 'index.html' in a plain text editor to change the og:image path. (Just make sure that the path you use is an absolute one.)

Just in case you are thinking of delving much deeper into this, the only user I know of who seems to have managed to overcome this restriction is sly from this thread.
His solution seems to be included within a rather complex custom JavaScript file (check out the 'jcaddon.js' file on his gallery pages) which overrides some of Juicebox-Pro's own sharing functionality and, therefore, is not officially supported.
(As such, I have not tested his solution myself and I cannot be sure that it will work across all platforms and in all browsers.)
However, I hope this points you in the right direction.

You og:image meta tag (in your gallery's 'index.html' file) is currently:

<meta property="og:image" content="/images/or_2011_05_0022.jpg" />

Facebook requires that the og:image path be an absolute path (rather than a relative path).

There are a couple of ways to fix this.

(1) Open your gallery in JuiceboxBuilder-Pro, go to the 'Customize -> Sharing' section, and enter the absolute path to the directory containing your 'images' folder in the 'Share Url' input box i.e.:

http://pascalriben.com/About Color/

Now re-save your gallery on the 'Publish' tab.
JuiceboxBuilder-Pro will use the 'Share Url' at the beginning of the og:image path and will append the path to the first image in the gallery after it.

... or:

(2) Open your gallery's 'index.html' file in a plain text editor and replace:

<meta property="og:image" content="/images/or_2011_05_0022.jpg" />

... with:

<meta property="og:image" content="http://pascalriben.com/About Color/images/or_2011_05_0022.jpg" />

(You can use the absolute path to whatever image you like.)

If, after making this change, you still do not see the image in the Facebook share window, then you might need to run your gallery's web page URL through Facebook's online debuggers to instruct Facebook to fetch new scrape information (including the og:image path) from your page.
(1) Facebook's Sharing Debugger: https://developers.facebook.com/tools/debug/sharing/
(2) Facebook's Batch Invalidator: https://developers.facebook.com/tools/d … ing/batch/
(3) Facebook's Open Graph Object Debugger: https://developers.facebook.com/tools/debug/og/object/
(Click the 'Fetch new scrape information' button.)

This should hopefully resolve your problem.

No worries!
I'm just glad to hear that your problems have been resolved.
Thank you for letting me know.