Unfortunately, the link you provided results in an error 404 (file not found).
Without being able to see the page into which you are trying to embed your gallery, it's very difficult for me to troubleshoot your problem.
As I mentioned earlier, if your 'Birds' folder is a complete Juicebox gallery folder, then the embedding code I provided should work fine in any web page throughout your site without modification. If it does not work, then the problem may be due to factors such as the 'Birds' folder being an incomplete Juicebox gallery folder or permissions issues (with files or folders on your web server being too restrictive).
If you can point me towards the web page that displays the "Juicebox Error: Config file not found." message (so that I can see the problem for myself), I should hopefully be able to help you further.

Try the following.
It's an extension of the original code I posted above so you'll need to make your owm modifications to it.
The additional code detects when the AutoPlay button has been clicked (to turn on AutoPlay) whilst the last image in the gallery is currently being displayed.

var jb = new juicebox({
    autoPlayOnLoad: "TRUE",
    containerId: "juicebox-container",
    showAutoPlayButton: "TRUE"
});
jb.onInitComplete = function() {
    var count = jb.getImageCount();
    jb.onImageChange = function(e) {
        if (e.id === count && $('.jb-bb-btn-auto-play').first().hasClass('jb-status-playing')) {
            window.setTimeout(function() {
                alert('Last image in gallery has been reached and 5000ms have elapsed.');
            }, 5000);
        }
    };
    $(document).ready(function() {
        $('.jb-bb-btn-auto-play').click(function() {
            var index = jb.getImageIndex();
            if (index === count && $('.jb-bb-btn-auto-play').first().hasClass('jb-status-playing')) {
                window.setTimeout(function() {
                    alert('AutoPlay button has been clicked on last image in gallery and 5000ms have elapsed.');
                }, 5000);
            }
            
        });
    });
};

I hope that you find the code useful and can implement it into your own website.

There's no benefit (as far as the gallery is concerned) to storing the configuration options via one method over the other.
Certain configuration options (for example, those referring to the structure of the gallery) must be used in the embedding code (Embed Options) but all others can be set in either the configuration file or the embedding code (whichever is more convenient).

I'd recommend storing the configuration options in the 'config.xml' file, though (as JuiceboxBuilder does).
This means that if you edit a gallery in the future, you just need to upload the new version of the 'config.xml' file (generated by JuiceboxBuilder) rather than having to manually edit the HTML file that the gallery is embedded into.

When you set a backgroundColor, it is written to the gallery's 'config.xml' file and also included in the gallery's embedding code. As noted here, any configuration options set in the embedding code will take precedence over those set in the 'config.xml' file.

Therefore, if you change the backgroundColor in JuiceboxBuilder-Pro and upload only the modified 'config.xml' file but still have a backgroundColor included in the gallery's embedding code, then it is this backgroundColor (from the embedding code) that will be used in the gallery.

Be sure to change the backgroundColor in your gallery's embedding code and all should be well.

If, after changing the backgroundColor in your gallery's embedding code, you still do not see your chosen color, then try clearing your browser's cache before reloading your web page to be sure that your browser is using the most recent versions of your gallery files.

Also, please note that if you are expanding a gallery from a Splash Page (for example in Small Screen Mode), then the gallery will only ever be visible in its expanded mode so you will see only the expandedBackgroundColor.

I hope these notes help to clarify things.

I still have no issue displaying your gallery in my own browsers (with empty caches).
All images in your gallery load quickly and completely for me.

The gallery is generated by the 'juicebox.js' JavaScript file. Essentially, Juicebox reads the imageURL data from the 'config.xml' file and displays the images via dynamically generated <img> tags (scaling the images according to the imageScaleMode value).

I see no problem with your gallery online and the variable factors in the equation are our respective internet connections and computers/browsers. The gallery itself on your web server seems fine and works for me so it appears that the problem lies either with your internet connection or computer/browser.

Unfortunately, I cannot explain why some images do not load for you. If your browser's developer tools suggest that the images are timing out before loading completely, then this sounds like a network connection problem.
Even if the problem was a JavaScript one (which seems unlikely as you are the only user to have reported such a problem), there is little that could be done as the 'juicebox.js' JavaScript file is obfuscated and cannot be modified.

• Do you see the same problem with any (or all) of our demo galleries online here?

• Do you see the problem in all browsers (Edge, Chrome, Firefox, Internet Explorer, Opera, Safari) or just certain ones?

• Have you tried temporarily disabling any browser extensions that you may have installed in the browser(s) that demonstrate the problem?

Juicebox does not have a debug mode (at least, not in the sense that you would need).
You can set debugMode="TRUE" in your gallery's 'config.xml' file (as noted here) but this just allows you to set configuration options via a query string in the URL (please see here for details) without needing to edit the gallery's HTML or XML files.

As you have mentioned 3G/4G, please also see this FAQ (although it sounds like you may already have switched 'no-transform' on).
Why can't I view my gallery on a 3G mobile connection?

You can make the caption area's background fully transparent by setting the Opacity to '0' for both the Caption Back Color and the Caption Back Top Color (in JuiceboxBuilder-Pro's 'Customize -> Color' section).

If manually editing your gallery's 'config.xml' file, set captionBackColor="rgba(0,0,0,0)" and captionBackTopColor="rgba(0,0,0,0)".

Please note that Juicebox-Pro uses only one captionBackColor and captionBackTopColor gallery-wide so the values you set will be used in both Small Screen Mode and Large Screen Mode.

When JuiceboxBuilder-Pro resizes images for a gallery, it converts PNG images into JPEG images and any transparent regions are rendered as black. Unfortunately, transparency is not retained in images resized for a gallery and it is not possible to pick the color for transparent regions.

The best thing to do would be to resize your images (as PNG images with transparency) in an imaging program (such as Adobe Photoshop) prior to using JuiceboxBuilder-Pro.
In JuiceboxBuilder-Pro's interface, deselect the 'Resize Images' checkbox (on the 'Images' tab) to prevent JuiceboxBuilder-Pro from further processing your images and your source images will be copied across to the gallery's 'images' folder (with transparency intact).

I hope this helps.

Awesome! Thanks for letting me know!

@haggis999

The rollover tooltip-text within a gallery is configurable via the languageList configuration option.
Please see the International Gallery Text support section for details.
This configuration option was intended to be used to translate the text into a different language but you can use to simply change the text if you like.
It is not available in the JuiceboxBuilder-Pro interface but you can add a custom languageList to your gallery's 'config.xml' file, as an attribute to the opening <juiceboxgallery> tag, alongside the other configuration options.
If you want to change "Expand Gallery" to "Hide Menu" and "Close Gallery" to "Show Menu", then you can use the following:

languageList="Show Thumbnails|Hide Thumbnails|Hide Menu|Show Menu|Open Image in New Window|Images|Next Image|Previous Image|Play Audio|Pause Audio|Show Information|Hide Information|Start AutoPlay|Stop AutoPlay|AutoPlay ON|AutoPlay OFF|Go Back|Buy this Image|Share on Facebook|Share on Twitter|Share on Google+|Share on Pinterest|Share on Tumblr|of|Send Email|Download|Password|Incorrect Password.|Regarding image|in gallery"

@haggis999

Thank you for all your suggestions!

Just in case it helps (and for anyone else reading this), when captionPosition is set to OVERLAY or OVERLAY_IMAGE, the height of the caption area is variable (it will increase, if necessary, to accommodate long captions) up to a maximum value set via maxCaptionHeight (default value, 120px). When captionPosition is set to BELOW_IMAGE, BOTTOM or BELOW_THUMBS, the height of the caption area is fixed at the maxCaptionHeight value. Either way, maxCaptionHeight can be increased to accommodate long captions.

As far as I am aware, jQuery $.ajax is used to GET the gallery's configuration file ('config.xml') and then the images are loaded into dynamically-generated <img> tags (having had their imageURLs read from the 'config.xml' file).

Is there something out of the ordinary about your internet connection/network that might be causing the problem?
Your gallery certainly looks fine to me.

I'd really need to see your Juicebox gallery's web page (even with the gallery failing to display) to be able to troubleshoot your problem specifically (to see what embedding code you use, what configuration options your gallery uses and to try to determine the location of the gallery files on your web server).
Otherwise, all I can do is give some generic pointers which may but may not be specific to your problem.
Please post back with the URL to your Juicebox gallery's web page so that I can take a look at the problem for myself and hopefully help further.

In the meantime, maybe the following will help.

As you have created a Flickr Set, you could easily create a Juicebox-Pro gallery from this Set as follows.
(1) Open JuiceboxBuilder-Pro.
(2) Click the 'New Gallery...' button on the 'Start' tab.
(3) Select 'Flickr' as the 'Image Source' (top left).
(4) Enter '72157692486109182' as the 'Flickr Set Id'.
(5) Click 'Load Images'.
(6) Customize your gallery on the 'Customize' tab (if you want to).
(7) Save the gallery on the 'Publish' tab (to a new empty folder of its own).

Now you have a Juicebox gallery displaying the images from your Flickr Set, you'll need to embed it into your WordPress site.
You can do this manually using the baseUrl method of embedding documented here. The baseUrl method of embedding is essentially the same as the regular method but it allows you to keep the entire gallery self-contained in its own folder. You would upload the entire gallery folder (not just its contents) to your web server and add a baseUrl entry to your embedding code, pointing towards the gallery folder. It does not matter where on your web server you upload the gallery folder to as long as the two paths in the embedding code (the path to the 'juicebox.js' file and the baseUrl itself, pointing towards the gallery folder) are correct.

Here's an example.
Let's say that you created a gallery (following the 7 steps above) and saved the gallery to a folder named 'flickr_test'.
You could embed the gallery into a WordPress page or post as follows:
(1) Upload the entire 'flickr_test' gallery folder to your web space's root directory.
(2) Edit the WordPress page or post that you'd like to embed the gallery into and paste the following embedding code into the body of the page or post (ensuring that the method of entry is 'Text' rather than 'Visual').

<!--START JUICEBOX EMBED-->
<script src="/flickr_test/jbcore/juicebox.js"></script>
<script>
    new juicebox({
        baseUrl : '/flickr_test/',
        containerId : 'juicebox-container',
        galleryWidth : '100%',
        galleryHeight : '600',
        backgroundColor: '#222222'
    });
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

The leading slashes in the paths above denote your root directory so the code above will work (without modification) in any page or post throughout your WordPress site.
(3) Publish the page or post.

Alternatively, you could do all of the above using WP-Juicebox, the dedicated Juicebox plugin for WordPress.
Here's how:
(1) Install WP-Juicebox to your WordPress site following the installation instructions on the plugin's support page here.
(2) Upgrade WP-Juicebox from Juicebox-Lite (which it comes bundled with) to Juicebox-Pro following the Upgrading to Juicebox-Pro instructions.
(3) Create a WordPress page or post that you'd like to display the gallery into and click the 'Add Juicebox Gallery' button.
(4) Select the 'Use Flickr' checkbox and enter flickrSetId="72157692486109182" into the Pro Options text area.
(5) Click the 'Add Gallery' button (at the bottom of the pop up gallery settings window).
(6) Publish the page or post.

That's it. The plugin handles the embedding code for you.

I hope these notes help but, as I mentioned previously, if you continue to experience difficulties, then please post the URL to your Juicebox gallery's web page so that I can take a look at the problem for myself and hopefully help further.
Once I'm able to see your (dysfunctional) gallery live on your web server, I should hopefully be able to determine the exact cause of your problem and propose a solution. Thank you.