Unfortunately, I don't have an iPad on which to test but your gallery's Splash Page (in your embedding web page) and the gallery itself both look OK on my iPod Touch. The Splash Page resizes correctly when changing orientation and, when the gallery has been expanded from the Splash Page, the images are displayed as large as possible within the gallery's image area (no matter what orientation the device is in).

Here are a couple of things I notice which might point you in the right direction.

(1) Your embedding page does not seem to be responsive in desktop browsers.
If the browser window is made more narrow, then the content on your web page does not adapt to the new width. The content is simply truncated (beyond the right-hand side of the browser window). This might be contributing to your problem in browser viewports of a certain width. Rotating your iPad might have a similar effect to changing the width of a desktop browser window (where your embedding page no longer fits the browser viewport).

(2) You have given your gallery dimensions of 100% x 100%. This might be perfectly OK but please check your gallery's parent container to see what dimensions have been assigned to it via CSS. A gallery height of 100% means that the gallery's actual height will be 100% of the height of its parent container. If the gallery's parent container has not been assigned a height via CSS, then Juicebox may not be able to determine what the gallery's actual height should be 100% of and this might cause your gallery to be displayed at unexpected dimensions.
Try giving your gallery a fixed pixel height (and try a few different values) instead of a percentage (at least for testing purposes). A gallery with a greater height will have a larger image area and this may allow the image to be displayed larger (depending on aspect ratios) with less space to the left and right.
Also, as your embedding page seems to be based on a fixed width, you might like to try giving your gallery a fixed width, too (to match that of your page).

If you continue to experience difficulties, please let me know the following:
(1) Does the problem happen only within the embedding page or also when the gallery has been expanded?
(2) What version of iPad do you have?
(3) What version of iOS do you run on your iPad?
(4) What browser (or browsers) do you see the problem in (Mobile Chrome, Mobile Firefox, Mobile Safari)?

Also, if possible, please provide screenshots so that I can see what you are seeing (as I do not have an iPad and cannot see your problem). You can attach images to a forum post if you like or upload them elsewhere and provide links.

Hopefully, once I'm able to see the problem (at least in screenshots), I should have a better idea of what might be causing it and might be able to propose a solution.
Thank you.

There is no way to move the caption area in Small Screen Mode: captionPosition is active in Large Screen Mode only.
In Small Screen Mode, the captionPosition is always set to OVERLAY, although the overlay can be toggled on and off by tapping the screen (or the Info Button if it is used). This gives the images as much room to be displayed as possible on small screen devices.
You could perhaps make your caption text stand out a little more by setting captionBackColor and/or captionBackTopColor (to give your caption area a more prominent background color instead of it being transparent) or by changing your textColor.

In Large Screen Mode, when you set captionPosition="BELOW_IMAGE", Juicebox uses the maxCaptionHeight value as an absolute value (rather than a maximum value) and this amount of space is always reserved for the caption area (no matter how much text there is to be displayed).
With the Showkase header and the reserved caption area below the images in the gallery, the images are probably being displayed as large as they can within the remaining space available.
By default, Showkase displays a gallery page such that the header and gallery are visible in their entirety (with the bottom of the gallery at the bottom of the browser window) so that users do not need to scroll to see any of the gallery.
The easiest way to increase the space available for the images would be to either reduce the maxCaptionHeight value (if possible) or set captionPosition to OVERLAY or OVERLAY_IMAGE.

If anyone else is reading this thread and experiencing a similar issue, please make sure that you are using the latest version of WP-Juicebox (v1.5.0.1) which can be downloaded from the plugin's support page here.

It looks like the problem was due to bug in WP-Juicebox v1.5.0 regarding the use of a custom permalink structure.
This problem was fixed in WP-Juicebox v1.5.0.1 (see the Version History page for a list of changes between versions) and upgrading WP-Juicebox to v1.5.0.1 should solve the problem.

@safeboat

Right-clicking is disabled within a Juicebox gallery but, in addition to showOpenButton (as noted above), there is now a direct download button (introduced in v1.5.0 - see the Version History page for a full list of changes).

Set showDownloadButton="TRUE" (in JuiceboxBuilder-Pro's 'Customize -> Button Bar' section) and the Download Button will be displayed on the gallery's Button Bar. Clicking this button will automatically initiate a download of the current image (without the need to open the image in a new page first).

You can check out the Download Button in this demo gallery (2nd icon from the left on the Button Bar).

By default, the Download Button will download the imageURL.
However, if you use a Multi-Size Image gallery and use large images, then the Download Button will download the largeImageURL
If you assign a linkURL to an image (to point towards a custom file), then the Download Button will download the linkURL instead.

Every gallery needs to have a separate configuration file (default name 'config.xml').
You can certainly set Config Options in the embedding code (please see here for details), but image data cannot be set in the embedding code and must be set in the configuration file.
Even if you use a Flickr account as a source of images and set the Flickr Options in the embedding code, the gallery still needs a separate configuration file (even if it is just a dummy file with only a <juiceboxgallery /> tag) to function correctly.

Please note that if a configUrl is not explicitly set in the embedding code, then Juicebox will look for a file named 'config.xml' in the same directory as the web page containing the embedding code.

I don't know what your goal is or if it will help you out but you could use a PHP script (or use some other server-side scripting language) to generate XML content on-the-fly when the gallery is displayed. Please take a look at this forum post (scroll down to the answer to Query #3) which has an example of how this could be achieved to display all images in a designated folder. (You could change the code to pull in image data from a database or whatever image source you choose to use.)

I appreciate you taking the time to post your suggestions in the forum.
However, if would be much better if you posted them in the Feature Request forum thread (a dedicated thread for ideas) where they will be seen by the developers and are less likely to get lost in amongst all the other support threads.
Thank you.

Incidentally, captions appear and disappear with their corresponding images so you might like to try setting imageTransitionType to either FADE or CROSS_FADE and then increasing the imageTransitionTime from its default value of 0.3 to something larger (although this will affect all image transitions, not just the initial image fade in).
Still, it might be worth trying a few different combinations in case you find something close to what you are trying to achieve.
(Both the configuration options in bold above can be found in the Main Image Options section of the Config Options page.)

You're welcome.

All you need to do to upgrade an existing gallery from Juicebox-Lite to Juicebox-Pro is replace the gallery's Lite 'jbcore' folder with the Pro 'jbcore' folder from the Juicebox-Pro zip package ('juicebox_pro_1.5.0/web/jbcore/'). This will instantly remove the image limit and branding and any Pro configuration options in the gallery's configuration file will become active.

You can also load a Juicebox-Lite gallery (using a local copy of the gallery on your computer) into JuiceboxBuilder-Pro (the desktop application to create and edit Juicebox-Pro galleries), configure the gallery with Pro options if you like (on the 'Customize' tab) and re-save the gallery on the 'Publish' tab. The gallery will be upgraded to Juicebox-Pro and you can then re-upload the gallery to your web server.

There is no way to change the imageURL prefix in JuiceboxBuilder-Pro. Images are always placed in a folder named 'images' and the imageURL paths always start with "images/". There are no user-changeable configuration options to change the name of the image folder or to set a different prefix for the imageURL. The code which handles this is compiled and cannot be modified.

If you want to use a different gallery structure to that created by JuiceboxBuilder-Pro, then you'll need to edit your gallery's 'config.xml' file in a plain text editor to change the imageURL paths.
However, if you use a text editor such as Notepad++, you'll be able to change all instances of "images/" to whatever you like across multiple files (if you have many galleries to change) in a single global search and replace action which should take just a matter of seconds.

You could modify the template 'index.html' file that JuiceboxBuilder-Pro uses to generate the gallery's 'index.html' file.
On a Windows PC, this template file is located here: C:\Program Files (x86)\JuiceboxBuilder-Pro\template\index.html
Try replacing the contents of this template file with the following. (I would strongly suggest that you take a backup of the original template file first, just in case anything goes wrong and you need to reinstate it at a later date.)

<!DOCTYPE html>
<html lang="en">
<head>
    <title>%%TITLE%%</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" />
    <meta name="description" content="%%DESCRIPTION%%" />

    <!-- START OPEN GRAPH TAGS-->
    <meta property="og:title" content="%%TITLE%%" />
    <meta property="og:type" content="website" />
    <meta property="og:url" content="%%GALLERY_URL%%" />
    <meta property="og:image" content="%%IMAGE_URL%%" />
    <meta property="og:description" content="%%DESCRIPTION%%" />
    <!-- END OPEN GRAPH TAGS-->

    <style type="text/css">
    body {
        margin: 0px;
    }
    </style>
</head>
<body>
    <!--START JUICEBOX EMBED-->
    <script src="jbcore/juicebox.js"></script>
    <script type="text/javascript">

        var purchaseURL;

        var strWindowName = 'Shopping Cart';
        var strWindowFeatures = 'menubar=yes,location=yes,resizable=yes,scrollbars=yes,status=yes,width=600,height=400';

        var jb = new juicebox({
            containerId: "juicebox-container",
            galleryWidth: '%%WIDTH%%',
            galleryHeight: '%%HEIGHT%%',
            backgroundColor: '%%COLOR%%'
        });

        jb.onInitComplete = function() {
            $('.jb-bb-btn-fotomoto').off('click');
            $('.jb-bb-btn-fotomoto').click(function() {
                var windowObjectReference = window.open('about:blank', strWindowName, strWindowFeatures);
                $.get('config.xml', function(data) {
                    var index = jb.getImageIndex();
                    purchaseURL = $(data).find('image').eq(index - 1).attr('purchaseURL');
                }).done(function() {
                    windowObjectReference.location.replace(purchaseURL);
                }).fail(function() {
                    windowObjectReference.close();
                });
            });
        };

    </script>
    <div id="juicebox-container"></div>
    <!--END JUICEBOX EMBED-->
</body>
</html>

A spinning logo usually indicates that an image cannot be found (perhaps due to an incorrect path in the gallery's XML file or a missing image on the web server).

If your gallery was working fine but now is not (and you have made no changes), then this suggests that something might have happened on your web server to cause the problem.
First of all, check that the paths to the images in your gallery's XML file are correct and that your images are present in their correct locations on your web server.
You might like to also contact your web host to ask if they have changed anything or have been experiencing any issues lately which might be contributing to your problem (maybe they have had some reason to reinstate your website from an incomplete backup).

If you continue to experience difficulties, please post back with the URL to your gallery's web page so that I can see the problem for myself and hopefully help further.
Thank you.