You can upgrade a Lite gallery to Pro by either of the following methods:
(1) Open the Lite gallery in JuiceboxBuilder-Pro(click the 'Open Gallery...' button on the 'Start' tab and select the gallery folder) and re-save it on the 'Publish' tab.
... or:
(2) Replace your Lite gallery's 'jbcore' folder with the Pro version from the Juicebox-Pro download zip file ('juicebox_pro_1.5.1/web/jbcore').

All image titles and captions will be preserved using either of the methods above.
If you open your Lite gallery with JuiceboxBuilder-Pro, you can change any of the configuration options (such as the Back Button options) on the 'Customization' tab before re-saving your gallery.

Deselect the Show Open Button checkbox in JuiceboxBuilder-Pro's 'Customize -> Lite' section.

You would use the embedding code to insert your gallery into an existing web page alongside other content.
All galleries need to be embedded into a web page. The 'index.html' files created by JuiceboxBuilder use the embedding code to embed the galleries into web pages of their own (with no other content on the web pages). If you open one of your gallery's 'index.html' pages in a plain text editor, you'll see the embedding code there.

You can save a combination of configuration options as a 'Preset' ('Presets -> Save Preset...' from the drop down menu at the top). You can then load this preset (to set all your custom configuration options at once and save you from having to set them all individually) via 'Presets -> Load Preset...'.
Please see the 'Presets' section of the JuiceboxBuilder-Pro User Guide for more information.

There is no progress bar when saving a gallery on the 'Publish' tab but the process should not take long at all.
The procedure that takes the longest time to complete is the resizing of the images and this is done when the images are added to the gallery on the 'Images' tab. (There is a progress bar for this, letting you know how many images have been processed and how many there are in total.) All that remains when the 'Save' button is clicked is to write the 'config.xml' file, add the custom embedding code to the 'index.html' file and move the resized images (and copy the 'jbcore' folder) to the specified folder.
You can always click the 'View in Browser' checkbox on the 'Publish' tab and JuiceboxBuilder-Pro will display the gallery (from the gallery folder) when the gallery is ready.

You can set the backButtonURL in JuiceboxBuilder-Pro's 'Customize -> Back Button' section.
The backButtonURL can be an absolute path, e.g. backButtonUrl="http://www.example.com/index.html"
... or a relative path, e.g. backButtonURL="index.html".
If using a relative path, the path will be relative to the web page containing the gallery's embedding code.

There is no configuration option named 'backButton' so if you manually edit backButtonUrl to remove the 'Url' part at the end, you will essentially have no backButtonUrl set and Juicebox-Pro will use the default behavior for backButtonUrl of going back one page in the browser's history.

If you want to create a new topic, select the forum you want to post in ('Juicebox-Pro Support' or 'Juicebox-Lite Support') and click the 'Post new topic' link just above the second blue menu bar at the right hand side of the page (see screenshot attached).

You're welcome.

If you are just upgrading a gallery from Lite to Pro (and not changing any of the images), then you can certainly just replace the gallery's 'config.xml' file and 'jbcore' folder. There is no need to re-upload any of the images. However, you could perhaps instruct your FTP program to upload only new or modified files and you could then give your FTP program the entire gallery folder and only the 'config.xml' file and 'jbcore' folder would be uploaded (to save you from having to pick them out individually).

You can save a custom combination of configuration options as a 'Preset' file ('Presets -> Save Preset...' from the drop down menu at the top).
When you next edit or create a gallery, you can apply this 'Preset' file to your gallery (to set all your custom configuration options at once and save you from having to set them all individually) via 'Presets -> Load Preset...'.
You can have as many 'Preset' files as you like (each holding different configuration option values).
Please see the 'Presets' section of the JuiceboxBuilder-Pro User Guide for more information.

You can delete an image by selecting its thumbnail with a single left-click (on the 'Images' tab) and then hitting Ctrl+D or going to 'Images -> Delete' from the drop-down menu at the top.
(You can also Shift-Click a block of images or Ctrl-Click a selection of images to delete.)

No problem!

Set showThumbsOnLoad="FALSE" in JuiceboxBuilder-Pro's 'Customize -> Thumbnails' section to initially hide the thumbnails.
You can also set showSmallThumbsOnLoad="FALSE" to initially skip the thumbnail page and go straight to the first image when the gallery is displayed in Small Screen Mode.

For reference, a list of all Thumbnail Options can be found here.

It might not be easy to seamlessly integrate text next to a Button Bar button but there is already rollover tooltip text associated with each button. When you mouse over the Thumbnail Button, the text 'Show Thumbnails' or 'Hide Thumbnails' (depending on the current thumbnail status) appears. If you like you can change this text via the languageList configuration option.

If you really wanted to display the text 'Toggle Thumbs' below the Thumbnail Button (for example), then you could try something like this:

<!--START JUICEBOX EMBED-->
<script src="jbcore/juicebox.js"></script>
<script>
    var jb = new juicebox({
        containerId: "juicebox-container",
        showThumbsButton: "TRUE",
        showThumbsOnLoad: "FALSE"
    });
    jb.onInitComplete = function() {
        $('.jb-bb-btn-de-show-list').append('<p style="font-family: sans-serif; font-size: 14px; padding-top: 10px; text-align: center;">Toggle Thumbs</p>');
    };
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

I hope this helps.

I see that the 'Photos' section of your website contains many photo galleries (listed under year headings).
I do not know how you are building your site (manually or with a web design program) but we have another software package named Showkase which you might be interested in.

Showkase is a PHP web application which allows you to create a complete portfolio web site (integrating multiple galleries) online.
Showkase has full support for Juicebox-Pro (and SimpleViewer-Pro) and the galleries can be created and managed within the application itself in a web browser interface. (Alternatively, you could continue to create Juicebox-Pro galleries with JuiceboxBuilder-Pro and then import them into a Showkase site.)

You can create Gallery Index pages (perhaps one per year as your current site does) and have as many galleries listed on each Gallery Index page as you wish.
Each gallery is represented by a thumbnail image with the gallery title displayed below and the gallery is opened when the user clicks on the image.
Demo sites created with Showkase (showing the different themes available) can be found here and a sample Gallery Index page can be found here.

Showkase can also create non-gallery pages (About, Basic and Contact pages) where you can add information about yourself (or any other content you like).
All of this is done automatically within the Showkase interface without the need for any manual coding at all.

Please feel free to take a look around the Showkase interface by logging into the Live Demo Admin.

Showkase can be purchased as Showkase-Standard (which comes with Juicebox-Lite and SimpleViewer-Standard, the free versions) or Showkase-Pro (which comes with Juicebox-Pro and SimpleViewer-Pro). The only difference between Showkase-Standard and Showkase-Pro is the bundled viewers.

As you already have Juicebox-Pro, you could purchase Showkase-Standard and integrate your Juicebox-Pro files by following the Installing a Pro Viewer instructions.

Just some food for thought that might make life a little easier if you are currently building and maintaining your web site by hand.

The current price for Showkase-Standard (which comes bundled with Juicebox-Lite and SimpleViewer-Standard, the free versions of the image viewers) is $45.
As you already have Juicebox-Pro, you could integrate your Juicebox-Pro files into Showkase following the Installing a Pro Viewer instructions.

The current price for Showkase-Pro is $95.
When you purchase Showkase-Pro, you'll get individual download links for Showkase, Juicebox-Pro and SimpleViewer-Pro.

You can purchase Showkase-Standard or Showkase-Pro from the Purchase Page.

Unfortunately, there are no discounts currently available for Showkase but as you have recently purchased Juicebox-Pro, you could either:
(1) Purchase Showkase-Standard ($45) and integrate your Juicebox-Pro files (following the instructions in the link above). You'd then have Showkase and Juicebox-Pro for the total cost of $90.
... or:
(2) Purchase Showkase-Pro ($95) and we'll refund you in full for your recent Juicebox-Pro purchase. You'd then have Showkase, Juicebox-Pro and SimpleViewer-Pro for the total cost of $95.

If you have no need for SimpleViewer-Pro (the Flash image viewer), then the less expensive option would be to purchase Showkase-Standard.
However, if you'd like SimpleViewer-Pro, too, then Showkase-Pro offers a saving of $40 over the total cost of all three individual programs (Showkase-Standard, Juicebox-Pro and SimpleViewer-Pro).

If you'd like to purchase Showkase-Pro and would like a refund for Juicebox-Pro, just let me know.
Thank you.