Yes. Set imageClickMode="OPEN_URL" (in JuiceboxBuilder-Pro's 'Customize -> Main Image' section) and, when a main image is clicked, the corresponding linkURL will be opened in the linkTarget window. (Ordinarily, when setting imageClickMode="OPEN_URL", the corresponding imageURL will be opened but if a linkURL has been assigned to the image, then this will be used instead.)

You can specify a unique linkURL and linkTarget for each image on JuiceboxBuilder-Pro's 'Images' tab.
Just click a thumbnail and the linkURL and linkTarget input boxes will be visible below the thumbnails.
(Otherwise, you can edit your gallery's 'config.xml' file manually in a plain text editor to add your linkURL and linkTarget entries as attributes to the <image> tags.)

A linkURL can be relative (to the web page containing the gallery's embedding code) or absolute (in the form 'http://www.example.com/files/file0001.pdf').

You're welcome!
I'm glad it was an easy fix! Thanks for letting me know.

If you are just upgrading an existing gallery from v1.5.0 to v1.5.1, then replacing a gallery's 'jbcore' folder is all that is necessary.

There are no changes to the gallery's embedding code (so no need to modify any of your HTML files), no changes to the syntax of the gallery's configuration file (so no need to modify any of your 'config.xml' files) and no changes to the gallery's structure (so no need to move or rename any gallery files).

I think you might be referring to a previous release whereby a meta tag was updated in the gallery's 'index.html' file and it was necessary to rebuild the gallery in JuiceboxBuilder-Pro to re-generate the 'index.html' file with the change. (Of course, this change was necessary only if you used the 'index.html' page to display the gallery on its own. If you embedded the gallery in an existing web page alongside other content, then this change was not required. Also, it was possible to just change the meta tag manually instead of having to rebuild the gallery.) There is no such change between v1.5.0 and v1.5.1.

If you are using the jAlbum skin to generate an album of galleries, then please note that there have been a few changes to the album's 'index.html' page (to fix a few small bugs) so, if you use this menu page generated by the skin, I recommend updating the skin and rebuilding your album to take advantage of the changes. (Existing images should not be re-processed by jAlbum when you click the 'Make album' button so the rebuild should be very quick.)

This issue has now been fixed in Juicebox v1.5.1 which has just been released (25 August 2017).
Please see the Version History for a full list of changes.
Full instructions for upgrading can be found on the Upgrading Juicebox support page.

This issue has now been fixed in Juicebox v1.5.1 which has just been released (25 August 2017).
Please see the Version History for a full list of changes.
Full instructions for upgrading can be found on the Upgrading Juicebox support page.

This issue has now been fixed in Juicebox v1.5.1 which has just been released (25 August 2017).
Please see the Version History for a full list of changes.
Full instructions for upgrading can be found on the Upgrading Juicebox support page.

This issue has now been fixed in Juicebox v1.5.1 which has just been released (25 August 2017).
Please see the Version History for a full list of changes.
Full instructions for upgrading can be found on the Upgrading Juicebox support page.

This issue has now been fixed in Juicebox v1.5.1 which has just been released (25 August 2017).
Please see the Version History for a full list of changes.
Full instructions for upgrading can be found on the Upgrading Juicebox support page.

This issue has now been fixed in Juicebox v1.5.1 which has just been released (25 August 2017).
Please see the Version History for a full list of changes.
Full instructions for upgrading can be found on the Upgrading Juicebox support page.

Yes. If you save your gallery to a folder which already contains a custom 'images' folder, then the contents of your custom 'images' folder will be deleted.
I'd recommend that you save your gallery to a new empty folder of its own and then make the required changes before adding the gallery files to your web project.

No, unfortunately not. There is no way to change the name of the 'images' folder or to use custom paths for the imageURL entries from within JuiceboxBuilder.
If you save the gallery to a folder of its own, then it would be very easy to just keep the gallery in its folder (without needing to make any modifications to the contents) and embed the gallery using the baseUrl method that I mentioned above.

No. The dimensions of the thumbnails can be defined only in absolute pixel values (and not percentages). The gallery itself will remain responsive (changing its layout to suit the available space) and this may result in fewer or more thumbnails being displayed per thumbnail page, but the dimensions of the thumbnails will always remain fixed (at the specified thumbWidth and thumbHeight values), no matter what device is being used to view the gallery. (The size of the main image and the number of thumbnails displayed can dynamically change depending on the size and shape of the browser viewport but the thumbnail size remains constant.)
I realise that this might not be the answer you were looking for but I hope that it at least helps to clarify things.

Perhaps the best course of action would be to compromise and set your thumbWidth to a value which gives you at least 2 columns of thumbnails on your small screen devices (and accept that this will also result in smaller thumbnails in desktop browsers, too).
Hopefully you'll find a balance that works.

In your 'kolarthy' web page, your gallery is the only element on the web page and it fills the entire web page with dimensions of 100% x 100% (so, technically, it is horizontally centered).

Using style="margin: 0 auto;" will horizontally center a div within its parent div.
The gallery has a width of 100% (so it spans the entire width of its parent div) and its parent div is the body tag (so the gallery spans the entire width of the web page).
The main images within the gallery are not centered within the image area (they are offset to the left) as your gallery sets imageHAlign="LEFT".

If you want a narrower gallery, horizontally centered, then reset imageHAlign to 'CENTER' (its default value), change your galleryWidth from '100%' to a smaller percentage or a fixed pixel value such as '800' and continue using <div id="juicebox-container" style="margin: 0 auto;">. You'll see that your gallery is horizontally centered on your web page.
(If you then remove style="margin: 0 auto;" and use just <div id="juicebox-container"> instead, you'll see the gallery is justified to the left hand side of your web page.)

If you were to replace the SimpleViewer embedding code in your 'galleryBW' web page with Juicebox embedding code (and set your galleryWidth to '100%'), your Juicebox gallery will replace your SimpleViewer gallery and, with a width of 100%, it will span the entire width of its parent div.
Instructions for embedding a Juicebox gallery into an existing web page alongside other content can be found here.

Hopefully this will help.
Please let me know if you get stuck with anything.