You currently have Showkase-Standard.

To be able to create Juicebox-Pro galleries (with no branding or image limit) with Showkase you could either:
(1) Purchase Juicebox-Pro from here and upgrade your Showkase installation by following the instructions here.
... or:
(2) Purchase Showkase-Pro (which comes bundled with Juicebox-Pro and SimpleViewer-Pro) and we can refund you for your Showkase-Standard purchase. (If you decide to do this, please let me know and I will send you an email so that you can forward me your transaction details for a refund.)

Please note that the only difference between Showkase-Standard and Showkase-Pro is that Showkase-Standard comes bundled with Juicebox-Lite and SimpleViewer-Standard (the free versions of the image viewers) whereas Showkase-Pro comes bundled with Juicebox-Pro and SimpleVIewer-Pro.

If you purchase Showkase-Standard and upgrade it manually with Juicebox-Pro and SimpleViewer-Pro, then you will end up with exactly the same files as if you had purchased Showkase-Pro.

You can set only a single font for gallery text using the galleryFontFace configuration option (in JuiceboxBuilder-Pro's 'Customize -> General' section).

If you want to use multiple fonts throughout your gallery, you can override the galleryFontFace by using HTML formatting (for elements such as the Gallery Title, Back Button and image titles and captions) as documented in these FAQs:
How do I add HTML formatting to image captions and titles?
How do I add HTML formatting to the Gallery Title or Back Button?

I would recommend saving preset XML files in a folder dedicated to preset XML files and then save each gallery into a separate folder. This should keep your preset XML files separate from your gallery files.

If you like, you can keep each gallery in its own individual folder, upload your complete gallery folders (not just the contents) to your web server and embed the galleries into your web pages using the baseUrl method of embedding.
Keeping each gallery in its own folder may help to keeps things organized on your web server.

You have purchased and are using Showkase-Standard (not Showkase-Pro).
You can check by looking at the text below the login panel on your Showkase admin login page. (Showkase-Standard displays only 'Showkase 1.2.0' whereas Showkase-Pro displays 'Showkase-Pro 1.2.0'.
Showkase-Standard comes bundled with Juicebox-Lite and SimpleViewer-Standard (the free versions of the image viewers) and Showkase-Pro comes bundled with Juicebox-Pro and SimpleViewer-Pro. (The only difference between Showkase-Standard and Showkase-Pro is the bundled viewers.)

You need to swap the entire Lite 'jbcore' folder in your 'showkase/admin/plugins/juicebox/master/' directory with the Pro 'jbcore' folder from the Juicebox-Pro download zip package ('juicebox_pro_1.3.3/web/jbcore/').

If your galleries are limited to 50 images and you see the Juicebox badge/link at the bottom-right corners, then your galleries are Juicebox-Lite galleries, not Juicebox-Pro. (Juicebox-Pro does not contain an image limit or branding.)

Instructions for upgrading Showkase to use a Pro viewer can be found here.
Be sure to rebuild your existing galleries after upgrading ('Pages (tab) -> Edit (gallery page)-> Advanced (tab) -> Rebuild this Juicebox gallery').

The page you linked to is a Drupal page.
Drupal is a Content Management System whose pages are not designed to fit completely within a user's browser window.
Vertical scrolling is normal and (on most Drupal pages) necessary to view all content on the page.
It would not be possible to constrict all content on a Drupal page to fit within a user's browser window (no matter what its size) without any scrolling.

You would have to manually construct your web page using the View Resizable Gallery with Top Menu Example sample gallery as a template. You can view the source of the web page in a browser, copy it and swap the header, gallery and footer for your own content.

Alternatively, you could try just reducing the height of your gallery (in your Drupal page) so that less vertical scrolling is necessary for most users.

[Post split to new thread.]

With Juicebox-Lite (the free version), it is not possible to add padding to a gallery from within the plugin's interface.
However, if you purchased Juicebox-Pro (and upgraded the plugin following the 'Upgrading to Juicebox-Pro' instructions on this web page), you would have access to the imagePadding and stagePadding configuration options which you could enter into the plugin's 'Pro Options' text area.
Please note that both imagePadding and stagePadding add padding to all four sides of the image and stage respectively (not just the top).

For reference, a list of all available configuration options can be found here.

Otherwise, you could edit the gallery's 'index.html' page after the gallery has been created and add padding above the gallery using CSS.

Unfortunately, the security restrictions in IE11, Chrome and Opera which prevent the loading of local XML files cannot be circumvented and so there is no possibility of previewing Juicebox galleries locally in these browsers (without using emulation).
As such, there is nothing we can do to allow users to preview Juicebox galleries locally in IE11 (or Chrome or Opera) in the future.

As arachnid says, you can use 'F12 -> Emulation -> Document Mode -> 10' (to emulate IE10) within IE11 (or use Firefox or Safari).

This problem seems to be isolated to Safari on a Mac.
I have viewed your galleries in Safari 5.1.7, Chrome 31, Firefox 26.0, IE11 and Opera 18 on a PC and all galleries I have tried expanding work fine in all browsers.

First of all, try clearing your browser's cache before reloading your web page to ensure that your browser is fetching and using the most recent files from your web server.

If this does not help, then try setting expandInNewPage="TRUE" in your gallery configuration options.
Please see here for more details about the expandInNewPage configuration option.

You could also try changing useFullscreenExpand from 'TRUE' to 'FALSE' to see if this makes a difference.
I realise that you may not want to change the value of this configuration option permanently but it may help to troubleshoot the problem.

With Juicebox, you could create many individual galleries (each with as many images as you like) but you would need to link them all together manually (possibly by following the Multiple Galleries instructions and examples here).

An alternative solution might be to use another one of our products: Showkase.
Showkase is a PHP web application (although it does not require or use a database) which allows you to create multiple galleries online in a browser interface and automatically have them listed and linked together on gallery index pages.
Demo sites can be found here and a sample gallery index page can be found here.

If you do not want to use PHP on your site at all, then Showkase would not be a suitable solution and you would need to assemble your site (incorporating multiple Juicebox galleries) manually on your computer and then upload it to your web server via FTP.

Another possible solution would be to use the Juicebox skin for jAlbum.
You would be able to drag and drop a complete folder structure into jAlbum's main window. A Juicebox gallery would be created for each folder/subfolder in your input structure and all the galleries will be linked together by a JavaScript navigation tree. A sample gallery with two folders can be found here.
The complete album would be created on your computer and you would then upload the files to your web server. (There is no PHP or database involved in this process.)

Your gallery's height is currently expressed as a percentage.
This will be a percentage of the gallery's parent container but, when the page is first loaded, the gallery's parent container is not visible and Juicebox may see its height as being 0px. 60% x 0px = 0px which may explain why the gallery is not displayed.

Instead, try expressing your gallery's height as a fixed pixel value (e.g. 600px) to see if this makes a difference.

If this does not help, then try also adding the gallery's height as inline CSS to the gallery container div, ie.:

<div id="juicebox-container" style="height: 600px;"></div>

... similar to the 'Using Percentage Heights' suggestion here.

Also, as you have multiple galleries which may be displayed on the same page, make sure you embed each gallery into a container with a unique id.

For example:

<script type="text/javascript" src="http://www.monpetitblog.net/galerie/2013_11_juice/jbcore/juicebox.js">

<script type="text/javascript">
new juicebox({
baseUrl : 'http://www.monpetitblog.net/galerie/path_to_gallery/',
containerId : "juicebox-container1",
galleryTitle: "Sept.'13",
galleryWidth: "100%",
galleryHeight: "600",
});
</script>
<div id="juicebox-container1" style="height: 600px;"></div>

<script type="text/javascript">
new juicebox({
baseUrl : 'http://www.monpetitblog.net/galerie/path_to_another_gallery/',
containerId : "juicebox-container2",
galleryTitle: "Sept.'13",
galleryWidth: "100%",
galleryHeight: "600",
});
</script>
<div id="juicebox-container2" style="height: 600px;"></div>

Incidentally, as you have WP-Juicebox activated, the 'juicebox.js' JavaScript file will be automatically loaded on your pages so there is no need to include the file in each and every gallery you manually embed.
(If you were to deactivate WP-Juicebox, you would need to include the file in each gallery's embedding code.)

As you note, your logo is currently part of your gallery's background (set via the backgroundUrl configuration option).
Instead, you could use either the Back Button or the Gallery Title as an image link.

In JuiceboxBuilder-Pro, you could enter the following into either the Gallery Title field (in the 'Customize -> Lite' section) or the Back Button Text field (in the 'Customize -> Back Button' section).

<a href="http://www.smallbusinessphoto.com"><img src="images/Logo-Dark.png" width="265" height="60" alt="logo" /></a>

For a link in the Gallery Title to be active, please set galleryTitlePosition="TOP" (in the 'Customize -> General' section).
The link will not be active if galleryTitlePosition="OVERLAY". (This bug will be fixed in the next version of Juicebox-Pro.)

If editing your gallery's XML file to add the configuration options manually, you will need to escape the XML entities as documented in this FAQ:
How do I add HTML formatting to the Gallery Title or Back Button?