HABERMAS  Using 10.5.1 - get just some boring repeating "geysir" of little particle balls. Lavalamps look about a hundred times better than this junk. Deleted it from my system one minute after downloading.

The screensaver doesn't come with an options menu yet it requires a full folder of datafiles be installed alongside it. Skip this junk and get a decent free screensaver like surveillancesaver, shufflesaver or Electric Sheep.  
(Version 1.0)

HABERMAS  By the way the "pan and scan" effect I'm refering to in the above seems to be called a "Ken Burns" effect. Is there any chance this could be implemented in the otherwise excellent ShuffleSaver?  
(Version 1.1)

HABERMAS  I tried this screensaver because I was hooked on the idea of a screensaver dynamically downloading and displaying random, high quality images from the net guided by user-configured queries.

Using flickr as the source repository ShuffleSaver comes very close to achieving that goal. Compared with RandomWeb - its closest competitor - ShuffleSaver generally delivers pictures of a higher quality and better within the theme described by the keywords.

However, ShuffleSaver's biggest letdown is its inability to mirror the essential pan and scan feature found in the original OS/X image slideshow-displaying Screensaver and faithfully reproduced by RandomWeb. The feature allows pictures of dimensions not fully corresponding to your desktop to fill your screen anyway by zooming in on a select sub-portion of the total image and then panning around the picture dynamically to gradually reveal more.

Because of this lack of functionality in ShuffleSaver I am currently torn between it and RandomWeb as my screensaver of choice - neither completely achieving my objectives.  
(Version 1.1)