This will shows when you will select Export Picture to File... from menu Menu
Units - You may choose Pixels, Inches or Centimeters as a mosaic size units.
Resolution - You need to set this value to allow the program to convert pixels units into inches or
Mosaic Width, Mosaic Height - You have to set one of these values, the other will be calculated
Save - Press this button to export/save file.
Show in Explorer - Use this button to quick find a saved file. It will opens a new Windows Explorer window
positioned at the folder where you have saved the image and with the image file selected.