A Juicebox gallery (both Lite and Pro) will dynamically resize with the size of the user's browser window as long as the dimensions of the gallery and all parent containers of the gallery are expressed as percentages.
If there is an absolute pixel value anywhere up the chain, then the gallery's size will be fixed, e.g. 100% x 100% x 800px = 800px.

Your gallery is a Juicebox-Lite gallery as can be seen by the presence of the Juicebox badge/link in the bottom right corner of your gallery (which is present in all Juicebox-Lite galleries but not in Juicebox-Pro galleries).
Juicebox-Lite has a limit of 50 images per gallery and does not use Juicebox-Pro configuration options such as enableLooping.

Upgrade your WP-Juicebox plugin from Juicebox-Lite to Juicebox-Pro by following the 'Upgrading to Juicebox-Pro' instructions on this web page and your gallery should function as expected.

Please take a look at the Troubleshooting FAQs to see if they help (the third one sounds like it might describe your scenario).

If you continue to experience difficulties, please post the URL to your gallery so that I can take a look.

Only you can decide what the best gallery dimensions would be for your own scenario/web page.

A Juicebox gallery will dynamically scale with the size of the user's browser window only if the dimensions of the gallery and the dimensions of all parent containers are expressed as percentages. If there is a fixed pixel value anywhere up the chain, the gallery's dimension will become fixed, e.g. 100% x 100% x 770px = 770px.

This is a valid use of hiding links and text according to this web page.

Try hiding the 'jbseo' <div> in your 'index.php' page using CSS such as either:

#jbseo {
    visibility: hidden;
}

... or:

#jbseo {
    display: none;
}

This may be caused be a conflict between the CSS on your page and that of the gallery itself.
Check your page's CSS (there are 30 external CSS files listed on your page) for any generalized CSS that the gallery might inherit. Look out for any CSS rules that, for example, apply to all 'img', 'p' or 'div' tags (rather than just specific instances of these tags through use of ids and classes).

To remove the padding around the titles and captions, try adding the following CSS to your gallery's 'jbcore/classic/theme.css' file:

.jb-cap-frame .jb-caption {
    padding: 0 !important;
}

As you are aware, Juicebox does not support positioning captions to the left or right of the main images but I notice that you have suggested this in the Feature Requests thread. Thank you for your suggestion.

Looking at the dynamically generated XML file for your gallery, the XML declaration is not at the very top of the document (where it should be). Line 1 of the file is blank.
Try viewing the file in a browser to see the error message: http://www.beavanderheijden.nl/site/wp- … llery_id=9
The file is created with the PHP function saveXML() so there should be no blank line before the XML declaration.

The cause may be due to a specific version of PHP. What version of PHP does your web server run and did your web host upgrade its PHP version recently?

The fix is to change line 148 of the 'wp-juicebox/config.php' file to the following:

echo $new_dom_doc->saveXML($new_settings_tag);

This fix will be included in the next version of WP-Juicebox.

To browse inside the 'juicebox.lrwebengine' package, use ctrl-click and select "Show Package Contents".

The drop shadow for the captions is not configurable from within the JuiceboxBuilder-Pro interface.
Edit the 'jbcore/classic/theme.css' file in a plain text editor and remove lines 215:

text-shadow: 1px 1px 2px rgba(0,0,0,0.5);

(The line number refers to Juicebox-Pro v1.2.0.)

Instructions for adding images to a WP-Juicebox gallery (for both WordPress prior to v3.5 and WordPress v3.5 or later) can be found on this web page (using WordPress's own terminology). Essentially, all you need to do is attach images to the post containing the gallery and the images will appear in the gallery.

The margin around the main image is controlled by the imagePadding configuration option. The imagePadding value is used in all directions (top, bottom, left and right) around the main image.
In order to use this configuration option in WP-Juicebox, you would need to upgrade the plugin from Juicebox-Lite (which it comes bundled with) to Juicebox-Pro by following the instructions on this page and then add imagePadding configuration option to the Pro Options text area in your gallery settings.
There are no configuration options to adjust the padding around the titles and captions, though you can set maxCaptionHeight (to ensure that the caption area's height does not go beyond a set value) and captionHAlign (to horizontally align the titles and caption within the caption area).
If you wish to configure a gallery beyond the available configuration options, you might like to look into modifying the gallery's 'jbcore/classic/theme.css' file. Please see the Theming Guide for further information.

We plan to introduce new configuration options in the next version of Juicebox-Pro which will allow you to horizontally and vertically align thumbnails and main images within their respective areas. Until then, make sure that you set low values for thumbPadding and imagePadding to minimize the space between the thumbnails and main images.

@Alfred

Upgrading WP-Juicebox should not cause this error message to be displayed. Try re-uploading the plugin files to your web server to ensure that all files are present and correct in case something happened to corrupt a file during the initial upload.

That is perfectly normal. That should be the only XML file in the 'wp-juicebox/' folder. The gallery XML files are stored in the 'wp-content/uploads/juicebox/' folder.

It sounds like your web server may not support the PHP function used to set the permissions on the 'wp-content/uploads/juicebox/' folder but as long as the permissions have been set to 0777 manually, the plugin should activate successfully.

Perhaps both of your problems are related. Please post the URL to one of your WP-Juicebox galleries which is displaying the 'Config XML Not Found' message so that I can take a look.