You can choose the following change frequencies: Seconds—10; Minutes—1, 5, 15, 30, and 60. Note that while you can drag the bottom right corner to enlarge the Flickr Widget, the dimensions of the next photo resize the widget during photo playback.
As well as displaying the photos in no frame at all, you can choose the following frames: Black Lacquer, Light Wood, Dark Wood, Simple Shadow, and Inset. Inset is a frame that puts the surrounding pattern into the frame and then gives a drop shadow to the frame over the photo, giving the impression that the photo sits beneath the screen.
When the photo size changes from photo to photo, the Flickr Widget resizes. Five options relate the origin for the resizing to the current photo itself: either the four corners or the center. A sixth option relates the origin for the resizing to the entire monitor display and where the Flickr Widget is placed in the display. This sixth option, Closest Corner, resizes the frame from whichever corner of the Flickr Widget that is closest to a corner of the display. As the size of the photos changes, the Closest Corner setting optimizes space on your desktop no matter where you put the Flickr Widget.
This standard tab is mostly self-explanatory. For more information about levels, see this article.