Thank you for providing the links to your galleries.
Although I was unable to see the problem in your galleries (as they are password protected), I was able to replicate the problem in a test gallery of my own using the same configuration options that your galleries use.

Unfortunately it looks like you've found a bug whereby the Back Button does not respect the buttonBarIconColor when a non-default value is used for buttonBarIconSize.
I have notified the developers and this problem should hopefully be fixed in the next version of Juicebox-Pro.

In the meantime, it looks like a suitable workaround would be to set buttonBarIconSize to its default value of 20.
This should hopefully be an acceptable workaround as you currently use a buttonBarIconSize value of 22.

Thank you for reporting this issue.
I hope my workaround helps until the problem is fixed.

This looks very much like a corrupt image (which has most likely happened during upload to your web server).
Try reuploading your images and clear your browser's cache before rechecking your gallery's web page.
If this does not help, then I would recommend trying a different FTP program to upload your images.
I personally use Filezilla (for Mac or PC). Its free and I've been using it for years without issue.
If you are a Windows user, then another free FTP program to try is WinSCP.
Hopefully changing your FTP program will help.

The Back Button should take on the buttonBarBackColor, the buttonBarIconColor and the buttonBarIconHoverColor (and this seems to work OK in a test gallery I've just created).

First of all, please make sure that you are using the latest version of Juicebox-Pro (v1.5.1) to ensure that any bugs from previous versions which have since been fixed are not contributing to your problem.
If necessary, instructions for downloading the latest version and upgrading existing galleries can be found on the Upgrading Juicebox support page.

Next, make sure that you do not have any custom CSS on your gallery's web page (for example if you use a custom theme) that might be overriding the gallery's own CSS.

I hope that these notes help.
However, if you continue to experience difficulties, please post the link to your gallery so that I can see the problem for myself and hopefully help further.
Thank you.

No. If you have a mix of both landscape and portrait images, then depending on your chosen values for thumbWidth and thumbHeight, either your landscape thumbnails or your portrait thumbnails will be cropped. (However, the main images in the gallery will be displayed in their entirety with no cropping, as long as imageScaleMode is set to SCALE or SCALE_DOWN.)

thumbWidth and thumbHeight apply to the whole gallery. It is not possible to set thumbnail dimensions for each image separately.

That sounds very strange (especially as the problem seems to be intermittent and not consistent).

First of all, if you are not already using the latest version of JuiceboxBuilder-Pro (v1.5.1), then you might like to try upgrading (upgrades are free within the same major version number) to make sure that any bugs from previous versions which have since been fixed are not contributing to your problem.
Please see the Upgrading Juicebox support page for details.

If you have any security software installed, try making an exception for the JuiceboxBuilder-Pro executable file (or temporarily disabling it) to see if this makes a difference. (Maybe it is somehow interfering with the JuiceboxBuilder-Pro processes.)

Maybe you could zip and upload your gallery folder somewhere (your web server or a file sharing service such as Dropbox) and provide a link so that I can try opening your gallery in JuiceboxBuilder-Pro on my own computer to see what happens.

Also, if there is any sequence of steps which you take to reliably reproduce the problem, please let me know so that I can try to replicate the problem on my own system and investigate further.
Thank you.

Only non-default values are written to the gallery's XML file (this prevents the need to always have an entry for each and every configuration option) so if you use the default value for smallImageWidth of 800, then there will be no entry for it in the gallery's XML file (and JuiceboxBuilder will use the default value of 800).

If you change a default value, then an entry will be written to the XML file. If you then change the value back to the default value, the entry will remain in the XML file and the default value will be seen. (This would account for smallImageHeight="600" being present in your gallery's XML file, even though 600 is the default value.)

As long as there is a 'small' folder of images in your gallery' 'images' folder and there are corresponding smallImageURL attributes for the <image> tags in your gallery's XML file, then everything is likely to be absolutely fine.

I hope this helps to explain what you are seeing.

'public_html' is the name given to the folder on your web server that represents your root directory.
As an example, if you were to upload a file named 'page.html' to your 'public_html' folder, then you'd be able to see the page by visiting http://alpinedescents.com/page.html
The folder name 'public_html' should not be included in any URLs.
With this in mind, the following should work fine:

<!--START JUICEBOX EMBED-->
<script src="http://www.alpinedescents.com/gallery/jbcore/juicebox.js"></script>
<script>
    new juicebox({
        containerId: "juicebox-container",
        baseUrl: 'http://www.alpinedescents.com/gallery/',
        galleryWidth: "100%",
        galleryHeight: "100%",
        backgroundColor: "rgba(34,34,34,1)"
    });
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

Incidentally, I notice that you can visit your website using either alpinedescents.com or www.alpinedescents.com. However, if you hardcode paths using 'www' in your embedding code, then the gallery will display only when visiting www.alpinedescents.com (but not when visiting alpinedescents.com).
Please see this FAQ:
My gallery works on 'www.example.com' but not on 'example.com' (or vice versa). Why?

Therefore, I'd recommend that you use relative paths within your embedding code and your gallery will then display on both alpinedescents.com and www.alpinedescents.com.

<!--START JUICEBOX EMBED-->
<script src="/gallery/jbcore/juicebox.js"></script>
<script>
    new juicebox({
        containerId: "juicebox-container",
        baseUrl: '/gallery/',
        galleryWidth: "100%",
        galleryHeight: "100%",
        backgroundColor: "rgba(34,34,34,1)"
    });
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

The leading slashes in the paths above denote your root directory so the code will work in any web page throughout your site without modification.

For any other users reading this thread and embedding galleries in Adobe Muse, the following two links may be useful.
Embedding With Adobe Muse: http://www.juicebox.net/support/embeddi … adobe-muse
Alternate Adobe Muse Embedding Instructions: http://www.muse-themes.com/blogs/news/6 … adobe-muse

You're welcome!

The solution in the FAQ really should work (I know of no other way to prevent content modification over a 3G/4G connection) and content modification will have the same effect on Juicebox (and many other websites which rely heavily on JavaScript) so if using 3G/4G really is the source of your problem, then you might need to resolve your problem before going forward with Juicebox. However, if the solution in the FAQ does not work for you, then this suggests that the problem may lie elsewhere (perhaps a Flash related issue).
We have a similar FAQ for Juicebox here:
Why can't I view my gallery on a 3G mobile connection?

If you'd like to switch from SimpleViewer to Juicebox, then I would recommend trying Juicebox-Lite (the free version) first. You can download Juicebox-Lite from the Download Page.
Try creating a Juicebox-Lite galley (check out our Getting Started guide), uploading it to your web server and viewing it over a 3G/4G connection to see how you get on.
If the gallery does not display, then the problem is almost certainly with 3G/4G and you might need to contact your 3G/4G provider and/or web host to see if they can help further.
However, if the gallery does display, then you should have no problem upgrading from Juicebox-Lite to Juicebox-Pro.

Please check your email. I have sent you a message regarding Juicebox-Pro and the discount for SimpleViewer-Pro users.

I think it is unlikely that a Windows update has caused your problem (although I'm not sure what might be causing your problem).

First of all, please try clearing your browser caches before reloading your gallery's web page to see if this makes a difference.

Also, if you have any browsers extensions installed, please try temporarily disabling them to see if this helps.

If you still cannot view your gallery in certain browsers, then please post a link to your gallery's web page so that I can take a look at the problem for myself. (You should be able to view your gallery in all major modern browsers: Chrome, Edge, Firefox, IE8+, Opera, Safari.)
Once I'm able to see your gallery, I should hopefully be able to determine the cause of your problem and propose a solution.

Yes.
Please see here for the Juicebox System Requirements.

I'm glad that you've been able to resolve your problem.
Thank you for letting me know.

Good news! I have heard back from Avast and they have now cleared the JuiceboxBuilder-Lite executable file's reputation in their database.
They say that the change may take up to 24 hours to take effect so, hopefully, you should have no problem running JuiceboxBuilder-Lite alongside Avast's Ransomeware Shield after your Avast database is next updated.