I currently use NextGen Gallery with Wordpress, however would like to transfer this to the "Thumbnail gallery" of JuiceBox.
You can use WP-Juicebox (the dedicated Juicebox plugin for WordPress) to create and edit Juicebox galleries within the WordPress Dashboard. When creating a gallery, just select 'NextGEN Gallery' as the 'Image Source' and type in the NextGEN Gallery Id.
1) Why would I need your new update ShowKase ?
Showkase is a PHP web application which would enable to you create a portfolio website online (complete with Juicebox-Pro and/or SimpleViewer-Pro galleries) via an internet browser interface. Showkase cannot be used in conjunction with WordPress.
2) Is there any way to import my captions, so I don't loose them (and don't have to re-type them all in again?)
If using WP-Juicebox to create your NextGEN-sourced Juicebox galleries, WP-Juicebox pulls in the image titles from the NextGEN 'Alt & Title Text' fields and the image captions from the NextGEN 'Description' fields.
I have tried the WP-Juicebox plug-in; however do not have a "Add Gallery" button (Google Chrome).
The 'Add Juicebox Gallery' icon or button is displayed in the toolbar on the 'Create' or 'Edit' post page. (In 'Visual' input mode, the Juicebox icon is displayed and in 'Text' input mode, the 'Add Juicebox Gallery' text button is displayed.)
I have just checked the current version of WP-Juicebox (v1.2.0) in Chrome 24 and I see both the 'Add Juicebox Gallery' icon and button.
If the icon/button is displayed in other browsers, then try clearing your Chrome browser's cache before reloading your page to see if this makes a difference.
If the icon/button is not displayed in other browsers, then check that you are using the most recent version of WP-Juicebox (v1.2.0), deactivate all other plugins and reactivate them one by one until you find a conflict. If you do find a conflict, please post back to let me know so that I can investigate further.
Also, when I do click on Default, I can select NextGen Gallery, enter in my ID # and title, then hit "Set" = but NOTHING is imported or added.
After entering your NextGEN Gallery Id and clicking the 'Add Gallery' button, a shortcode such as the following should be entered into the body of the post.
[juicebox gallery_id="1"]
If this does not happen, then you may have another plugin installed which is conflicting with WP-Juicebox.
Once again, please check that you are using the most recent version of WP-Juicebox (v1.2.0), deactivate all other plugins and reactivate them one by one until you find a conflict.