Thanks for the reply, but still having problems.  I set Gallery Height to 830 pixels.  When viewing on large resolutions the thumbs are at the bottom of the screen and the image at the top with a massive gap between.  I have imageSCALEmode set to NONE as I do not want the image to be scaled.  I have also cleared out the browser cache and still have the same problem.  Any ideas?

Okay, the problem seems to be that if I set a fixed gallery width/height, the scale options no longer work (hence the forced scroll bar). If working with a percentage then they do.  My current gallery is set at 100% on both vertical and horizontal, the gallery works great on all devices with exception to those using large resolutions in which you get a big white gap between the image and the thumbnails.  There must be a way to solve this without resorting to using massive images?  If I use image Valign to center it looks just as odd.  I am an artist hence reluctance to use large images.

So, I have decided to go with a larger size image 1920x1200 - I will just watermark them (and lower quality a bit).  This seems to be working better - in terms of white space between thumbs and images and how it manages real estate.  The only niggle I have is that the Juicebox frame is taking over and ignoring the fixed left hand frame in most resolutions? If you open  http://www.martinturnerartist.com/index2.html you should see what I mean.  Help very much apppreciated.

Thank you for the updates.
I'm glad that you've been able to resolve your problem.
Thank you for letting me know.

Here are a few notes which might help to clarify a couple of things.

If you set a gallery's height to be a fixed pixel value, then the gallery height will always be the specified value and a vertical scrollbar will appear if necessary.
If you set a gallery's height to be a percentage value, then the gallery's actual height will be the specified percentage of the gallery's parent container. If there is no other content on the web page, then the gallery's parent container will be the 'body' tag and setting a gallery's height to be 100% will mean that the gallery's height will always fill (be 100% of) the browser window height.

Using larger images or changing imageScaleMode to either 'SCALE' or 'FILL' are the only ways to have your gallery images fill a larger area and minimize the space surrounding them.

If the browser window is much larger than 1024 x 768 and you want your images to be displayed at no more than 1024 x 768, then there will be empty space somewhere. Setting imageVAlign to 'CENTER' (the default value) to split the empty space equally above and below the image is usually a good visual solution. Unless you set your gallery's width and height to be fixed pixel values (i.e. if you use percentages), you essentially have no control over the aspect ratio or size of your gallery and trying to have a gallery look good in a myriad of different viewport shapes and sizes is never going to be easy. If you know that your target audience is likely to be viewing your gallery on large desktop monitors (or, conversely, on mobile devices), then you can tweak your gallery to perhaps look better in one viewport shape than another but, often, compromises may have to be made so that galleries look 'good' everywhere rather than 'great' in certain aspect ratios but 'poor' in others.

That sounds like a good solution to me!