A set of options that control different aspects of the program are available from the main program window (figure bellow)
More specifically:
Folder to scan for data: Contains the folder to be scanned for images.
Include subfolders: check this checkbox if you want to scan recursively all subfolders of the selected folder for images.
Order: Use this radiobutton group to select the order with which the slides are presented. "Unsorted" means that the images will be presented with their ordiginal order (the order they are written in the file system).
Wallpaper Style: Use this radio button group to select how images are projected on the desktop. The available options are: tiled (the images are displayed in their original size, tiled to form a mosaic, if they are smaller than the desktop), center (images are displayed in their original size, centered in the middle of the desktop), and stretch (the images are stretched to the size of the desktop).
Stretching options: This group of options is only enabled if the wallpaper style is set to "stretch". If "Keep ratio" is selected, stretching is performed in a way that guaranties that the original aspect ration (width to height ratio) of each image is maintained). The other two options ("strech from inside" and "stretch from outside") are used to define how stretching is performed if "keep ratio" is selected. The first option ensures that the whole image will be visible event if this means that the some part of the desktop will not be covered by the image. The second option ensures that the image covers the whole desktop, even if this means that a portion of the image will be outside the desktop.
Background color: This is the default background color of the desktop. The background color may be visible either when the "center" wallpaper style is selected and the image is smaller the that size of the screen or when no image is selected to be displayed. For the former case (when the image is smaller that the screen), the "automatic color selection" checkbox is useful in that is tries to select a background color that matches the background color of the image. In no image is displayed, the default background color is used.