The picture previewer is a separate window which can float on top of other windows or behave in the normal overlapping fashion.  When kept in front, the preview window can be used to quickly look through all of your digital pictures.  To do this, be sure the "Front" button is toggled on, then simply change the currently selected specimen record using the Specimen List.  You can use the up and down arrow keys to scroll through your entire collection in this way.

The six buttons at the top of the window have the following use:

 

Button	Usage
Fit	Show the entire picture within the boundaries of the window.  When you resize the window the picture will shrink or expand to fit entirely within the window
Full	Show the picture at full size.  This is the pixel-for-pixel representation of the picture shown without any compression or expansion in size.
Front	Keep the picture preview window on top of all other windows.  Use this option when scrolling through your specimen list.
Back	Place the picture preview window behind other windows when it isn't the active window.  This is the normal behavior for windows.
Print	Print the full sized picture
Close	Close the picture preview window