GETTING STARTED
Step 1 - You must set the folders from which a random picture will be chosen. Select a folder in the Finder that contains: Images
or Folders that contain images. Then click the set button to the right of one of the folder slots. If the selected folder contains images then those images will be used. If the selected folder contains a folder or folders, then all the images within those nested folders will be used and any images in the selected folder will be ignored.
Example: You select folder A which contains folders B & C. The images in folders B & C will be used, while the images in folder A will be ignored. Folder D which is in folder C will also be ignored.
Note: All the files in a folder are eligible to be chosen - even files that are not pictures - so it is best to select folders that contain images only.
Step 2 - Of the folders you have set, activate the ones from which you wish to have a random picture selected by clicking on the checkbox to the left of the folder slot.
Step 3 - Click the Change Picture button.
AUTO-CHANGE

To have the desktop automatically change after a certain time interval, enter the desired number of seconds in the box that looks like a big front tooth. Then click on the checkbox that looks like a nose to toggle Auto-Change on/off. If the number of seconds is greater than 30 then there will be a beep when the picture has changed.
Explanation of Various Buttons

Opens the current desktop picture in Preview.

Opens the folder that contains the current desktop picture.

Sets the desktop to the file currently selected in the Finder.

Sets the desktop to the favorite pic.

Saves the current desktop picture as the favorite pic.
Technical Note on Folders & Randomness
If you have two folders activated, with folder A containing 3 images and folder B containing 500 images, you will see the 3 images from folder A much more often than the 500 images in folder B. The reason for this is that the widget first chooses randomly between the two folders and then it chooses a random image from that folder.
If the chosen folder contains folders, then the widget randomly picks one of those folders and then chooses a random image from that nested folder.