Hi Ken
At the bottom of the gallery window, to the left of the film strip, there is an icon that looks like a cog.
When you click this icon a menu appears where you can select the 'Admin Console', 'Show Slider', 'Faster', 'Medium', 'Slower', and/or 'Auto Expend'.
If you select 'Auto Expend' the image is scaled to the maximum height and/or width that will fit in the gallery window.
This is the condition the I was meaning by 'Auto Expend Mode'.
regards
Bazzag