Here are two more suggestions that might help.

(1) Rather than using the default setting of expandInNewPage="AUTO", try setting expandInNewPage="TRUE" (to always expand the gallery from the Splash Page in a new page of its own) or expandInNewPage="FALSE" (to always expand the gallery on top of the embedding page). You might find that one of these settings works. (You can find the expandInNewPage configuration option in JuiceboxBuilder-Pro's 'Cuistomize -> General' section.)

(2) Also, when nesting the gallery within parent containers and giving your gallery percentage dimensions, it may be necessary to ensure that all parent containers have dimensions specified via CSS.
For example, if your gallery has a height of 100%, then Juicebox needs to know what its actual height should be 100% of. If the gallery's parent container does not have a height specified via CSS, then Juicebox may not be able to determine the gallery's actual height.
Please see this note regarding Using Percentage Heights.

Hopefully one of these two suggestions will help.

I'm not exactly sure what is causing your problem but your embedding code is a little non-standard (loading the 'juicebox.js' file from a location other than a 'jbcore' folder, using JavaScript to set configuration options in an external file and running the setGallerySize() API method when the resize event is fired) and might somehow be contributing to your problem.

Here are a few things you could check or try.

(1) See if the problem happens in our own Pro Embedded demo gallery.
This might help to determine whether or not the problem is unique to your own web page.

(2) Try locking the viewport on your web page. Change:

<meta name="viewport" content="width=device-width, initial-scale=1.0">

... to:

<meta name="viewport" id="jb-viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=0" />

(3) You have set buttonBarPosition="NONE". This disables the entire Button Bar, including the Expand/Close Button which is the recommended method of closing an expanded gallery. Try setting buttonBarPosition="OVERLAY" and showExpandButton="TRUE" and try closing the expanded gallery with the Expand/Close Button (to return to your main page).

(4) Try embedding a more basic gallery into your main page as a test case using the recommended baseUrl embedding code here (rather than using your custom JavaScript code). If this works, then you can introduce elements of your custom JavaScript code to see if you can find the source of the problem.

I'm not sure if any of these suggestions will work but I hope they at least point you in the right direction.

Make sure that you uninstall any existing version of JuiceboxBuilder-Pro first before installing a new version.
Mac: Delete the 'JuiceboxBuilder-Pro' file from the Applications folder and empty your Trash.
Windows: Use the uninstaller in the 'Control Panel -> Programs -> Uninstall a program...' list.

If you run into any problems, then the Installation Issues section of the JuiceboxBuilder-Pro User Guide may help.

If this still does not help, then please try the procedure outlined in this forum post.

Also, I would recommend that you use the latest version of Juicebox-Pro (v1.4.4.2) rather than v1.3.1 as many bugs have been fixed since v1.3.1. Please see the Version History for a list of changes between versions.
You can download the latest version using the download link from your purchase email. Full instructions can be found on the Upgrading Juicebox support page.

If you continue to experience difficulties, please let me know exactly what the problem is (what error messages are displayed, if any) and I will try to help further.

If you are looking for examples of Juicebox galleries, then you might like to check out our own demo galleries here.

We have also highlighted several other users' galleries in our Facebook page, our Twitter feed and our blog.

The easiest way to showcase a Juicebox gallery on the web would be to upload the complete gallery folder to a regular web server via FTP. You can then load the gallery's 'index.html' file in a browser to view the gallery.
Juicebox galleries can also be displayed in web template sites by following the instructions here.

Keyboard controls seem to work fine for me on the first image in your gallery as soon as the web page has loaded (in Chrome, Firefox and Internet Explorer on PC).
If the gallery is embedded in a web page alongside other content, then you would need to click on the gallery to give it focus before keyboard controls would work but this should not be necessary in a full page gallery (where the gallery's dimensions are 100% x 100% and it is the only content on the page).

Try completely clearing your browser's cache before reloading your web page to see if this helps.

To automatically give your gallery focus after the web page has loaded, you could try something like the following:

<script type="text/javascript" src="jbcore/juicebox.js"></script>
<script type="text/javascript">
    var jb = new juicebox({
        containerId: 'juicebox-container',
        galleryWidth: '100%',
        galleryHeight: '100%',
        backgroundColor: 'rgba(223,223,223,1)'
    });
    jb.onInitComplete = function() {
        $('#juicebox-container').find(':first-child').focus();
    };
</script>
<div id="juicebox-container"></div>

That's great! Thanks for letting me know.

According to your gallery's 'config.xml' file, the first image in your gallery should be located here: http://eye.de/gal-html5/marilena/images … _1000h.jpg
... but going directly to that location in a browser results in an error 403 (forbidden).

Please check that your thumbnail and image files have been uploaded to the correct locations on your web server and that their permissions (and the permissions of the 'thumbs' and 'images' folders themselves) are not too restrictive.
Default permissions of 755 for folders and 644 for files should be fine.

You can check and change permissions with an FTP program such as Filezilla or via your web hosting account's online file manager.

Also, please see this FAQ which may help:
My images show locally, but not when I upload them to my website. Why?

I have just tried embedding a gallery on Google Drive at less than 100% x 100% (at a fixed size of 600px x 400px) in a web page setting showSplashPage="ALWAYS" and trying both expandInNewPage="FALSE" and expandInNewPage="TRUE". The gallery expands correctly in both scenarios on my iOS device and in desktop browsers.
Here it is with expandInNewPage="AUTO":
https://7e149673cba79128b4d3fe7ac7a9b89 … index.html

I get an error 400 when trying to switch galleries on your web page (as well as when trying to expand a gallery from the Splash Page) so I think the problem might have something to do with the code on your web page and the way that your galleries are embedded or loaded.

As the problem happens when clicking one of your gallery links, you should have more control in debugging the switching of your galleries than the expanding of the Splash Page (although, being that the error messages are the same for both scenarios, they might be related to each other).

I would try debugging your web page's JavaScript code to ensure that all your variables are set as you expect them to be.
This should hopefully help to track down the cause of the problem.
After setting a variable but before using it, use a JavaScript alert box to check its value to see if it is what you expect it to be or if it is perhaps undefined for some reason (maybe due to a limitation in using Google Drive rather than a regular web server).
Check that everything is OK before running your new juicebox(content.options); line of code.

I would also try stripping back your custom JavaScript code so that only basic functionality exists.
You could then reintroduce elements, one at a time, to see if you can find the cause of the problem.

I realise that this does not directly solve your problem but I hope it at least points you in the right direction.

You might also like to look into the possibility of hosting your web site on a regular web server rather than on Google Drive.
Juicebox does not require any special server requirements so most web hosts (even those offering free web space) should be suitable.

Thank you for providing the URL to your test page.

I have done some further investigation and it looks like the problem may somehow be related to the meta viewport tag on your main page.

I have loaded a default full page gallery into an iframe which takes up 80% of the page's width (just an arbitrary value that is not 100% so that any problems can easily be seen).
On changing orientation and then changing it back, there is no resizing and the gallery always fills the iframe and the iframe always fills 80% of the page's width.
Here is the test gallery.

As soon as I introduce a meta viewport tag into the page, such as the one you use in your web page (below), there are resizing problems (not exactly the same as yours but resizing problems nonetheless).

<meta name="viewport" content="width=device-width, initial-scale=1">

I don't know if anything can be done from within the iframe page (the gallery) but one possible workaround would be to refresh the page when the orientation changes. This will reset the page layout each time the device's orientation is changed.
This can be achieved by adding the following JavaScript code on your web page:

<script>
    window.onorientationchange = function() {
        window.location.reload();
    };
</script>

This might not be an ideal fix but it should work.
(The best solution would probably be to embed the gallery directly into your web page and not use an iframe but I realise that this is not possible with a web template site such as Squarespace.)

You might find the following two forum threads interesting.
http://stackoverflow.com/questions/1080 … ion-change
http://stackoverflow.com/questions/7919 … ion-change

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

That's because the gallery is embedded in a web page at 100% x 100% with no other content on the page.
The gallery is not actually embedded into your main page. The gallery is embedded into the page which is loaded into your iframe. (This is the page which contains the gallery's embedding code.)
The Splash Page is displayed only when a gallery is embedded in a web page at less than 100% x 100% (or if showSplashPage="ALWAYS").

The best thing to do would be to post your suggestion in the Feature Requests forum thread.
This keeps all the ideas together and ensures that they are not overlooked by the developers.
Thank you.

Please note that we did not write the Juicebox module for Drupal ourselves and if you have any queries relating directly to the module, I would recommend that you post in the Drupal forum where the author of the module (who will be more familiar with both Drupal and the module itself) should be able to help you out further: https://www.drupal.org/forum
The Juicebox module for Drupal is an unofficial plugin but is well supported by its author on the Drupal forum.

Also, the link you provided points towards an alpha (pre-beta) version of the module so there may well be bugs in it.
If you find any, I'm sure the author of the module would be very grateful to know about them so that they can be tracked down and fixed.

Having said that, your problem sounds likely to be related to either the location of the Juicebox files on your web server or the permissions of the files (or parent folders).
Please double-check that you have uploaded the contents of the 'jbcore' folder to the correct location on your web server, step #3 in the instructions here: https://www.drupal.org/node/2000300
Copy the contents of the 'jbcore' folder (not the 'jbcore' folder itself) into the '/sites/all/libraries/juicebox/' folder on your web server.

Also, make sure that the permissions of the files and folders in the path are not too restrictive.
Default permissions of 755 for folders and 644 for files should be fine.

I realise that this may not directly solve your problem but I hope this points you in the right direction.