SimpleViewer is no longer available (it was the Flash predecessor to Juicebox's HTML alternative).
Users can still download Juicebox-Lite (the free version) from here.
However, for full access to all customizations (including all 21 Pro-only Thumbnail Options), we recommend Juicebox-Pro.

If you are referring to the 'Simple' layout used in one of our demo galleries (inspired by a SimpleViewer layout), then this is available as a ready-to-use preset in JuiceboxBuilder-Pro (on the 'Customize' tab). Unfortunately, a lot of the configuration options used in the 'Simple' layout are Pro-only and are not available in Juicebox-Lite (the free version).

Google Translation:

Vous pouvez régler ou modifier la taille d'affichage des vignettes ( WIDTH , HEIGHT ) , le nombre de colonnes (COLUMNS) et de lignes (ROWS) , et l'entourage par un bordure plus ou moins épaisse, et les couleurs de cette bordure ; y compris la forme Rectangle pur ou coins arrondis.

It appears from one answer in your forums that your Javascript program would display a webp image if it was listed in the xml file.  But your JuiceboxBuilder-Pro (and I'm assuming LITE) doesn't support building an xml with webp images.  So a separate step would be needed to "edit" the xml.  And the user would have had to created two sets of files:  one jpg and the other webp.  This would be time-consuming and error prone.

Edit:  update.  After getting JBPRO working (another topic) I created a gallery with a handful of images ... all jpgs.  Tested and it worked fine.  Used photoshop to create webp versions of all the images and corresponding thumbnails.  Used an editor to edit the xml file changing all ".jpg" to ."webp."  That's straightforward enough.  Loaded both versions of the gallery and all the jpg and webp images to a local Drupal test site.  Both versions of the gallery display fine.  So this works.  It would still be so much better if JBPRO supported webp from the outset.

You can set up your own payment pages (using whatever payment system you like) and then point towards them from within your Juicebox-Pro gallery using purchaseURL entries in your gallery's configuration file.
Please see here for details: Shopping Cart (scroll down to the 'Using Custom Purchase URLs' section).

The mock-up on the home page is not a 100% accurate representation of the same gallery across different devices (at least not a gallery with default configuration settings).

In Small Screen Mode, the thumbnail icon (to switch between the thumbnail and main image pages) is a 3 x 3 grid of nine dots.
In Large Screen Mode, the thumbnail icon (to toggle the thumbnails on and off) is is small representation of a main image with 3 thumbnails below (i.e. the thumbnail icon seen on the smallest device in the mock-up).

The other icon seen in the mock-up is the Open Image button which will be displayed is you set showOpenButton="TRUE".

You would see what you see on the smallest device in the mock-up if you set the following configuration options:

screenMode="LARGE"
showOpenButton="TRUE"
showThumbsOnLoad="FALSE"
showThumbsButton="TRUE"

You'd also need to set imageScaleMode="FILL" to have the image fill the viewport (with cropping) as seen in the mock-up.

I was just on the Juicebox home page and noticed this:

Do I have my galleries setup incorrectly? No control buttons for me.

DX2300

Thank you for the suggestions!
Your feedback is genuinely very welcome.

I just though I''d make some notes regarding the points you make.
I know my notes will not help to resolve any of the issues you raise but I thought I'd share some information on these topics as some background information may be helpful to others reading this thread.

If the gallery is a full-page gallery (or if you expand the gallery so that it fills the viewport), then as long as you set imageScaleMode="SCALE" or imageScaleMode="SCALE_DOWN", the images should be displayed in their entirety, respecting their aspect ratios and without any cropping.

I understand that in such a scenario, you might want to zoom into an image but, as you are aware, there are issues with pinch-zooming...

Unfortunately, it can be very difficult to pinch-zoom within a Juicebox gallery as a pinch-zoom gesture can often be misinterpreted as the start of a navigation swipe within the gallery (so, for a full-page or expanded gallery, Juicebox locks the viewport of the web page to avoid such issues).
There is no easy solution to make Juicebox gallery images easily zoom-able. (Juicebox does not have any built-in zoom functionality.)

If you'd like to zoom into an image, then the best course of action is to open the image on a page of its own first via the gallery's 'Open Image' button (by setting showOpenButton="TRUE" in JuiceboxBuilder-Pro's 'Customize -> Lite' section) or by tapping/clicking the main image (when setting imageClickMode="OPEN_URL" in the 'Customize -> Main Image' section).
Once the image is displayed on a page of its own, it can be zoomed with ease (and without adversely affecting the gallery itself).
Of course, afterwards, you need to use the browser's own back button (or tab/window selection tool) to return to the gallery page.
(I realise that this will help only with the image itself and not its caption text. Your feature requests are valid!)

Thanks! We're glad you like it! :)

Still one of the best out there.

DX2300

It has, indeed, been a while since the last release but please let me reassure you that Juicebox is still actively being developed and supported.
The next version will likely be a bug-fix version, rather than introducing new features. Work has started on the next version but progress is rather slow (and I do not know when it will be released).
However, I hope to see a new release soon, just as much as you do!