You can do this by working with the "Fixed Layout option". Open the options.as in the source folder and where it says
static var fixedLayout:Boolean = false
change false to true. then scroll down the page until you come to "//Fixed Layout Positions"
static var imageAreaX:Number = 10; //X posn of Image Area
static var imageAreaY:Number = 10; //Y posn of Image Area
static var imageAreaWidth:Number = 480; //width of Image Area
static var imageAreaHeight:Number = 480; //height of Image Area
static var thumbAreaX:Number = 500; //X posn of Thumb Area
static var thumbAreaY:Number = 10; //Y posn of Thumb Area
in the imageAreaWidth:Number = 480; //width of Image Area and imageAreaHeight:Number = 480; //height of Image Area is where you change the max width of you image area so if you want the thumbs on the right all you have to adjust is the imageAreaWidth:Number = 480 (as an example only) your image is 200 pixles wide to put the thumbs at the 260 mark add 460 (to account for the 200pixle image) to the image area size. Remember that the image size is measured from the top left of the image.
To adjust the placement of the main image in the "//fixed layout" area go to
static var imageAreaX:Number = 10; //X posn of Image Area
static var imageAreaY:Number = 10; //Y posn of Image Area
from there you can place it anywhere on the page.
I have done this and found that it is trial and error to get things just like you like but it will work.
Hope this helps.