Just after the end of your 'juicebox-container' div, you have an HTML line break (<br />).
If you remove this, then there will be a little less space between the bottom of the gallery and your text.
Also, you have set thumbNavPosition="BOTTOM". This reserves space below the thumbnails for the thumbnail navigation buttons. If you set thumbNavPosition="CENTER" instead, the thumbnail navigation buttons would be positioned to the left and right of the thumbnails and there would be less space below the thumbnails.
If you are having trouble with space above and below your images (within the gallery), then this FAQ might be helpful.
My Juicebox gallery shows too much space above or below the main image, how do I fix this?