admin@plentyofsoft.com presented the following explanation :

I don't know if this is what you are referring to but have a look here:

http://www.chaucery.com/jme/fleace/

Fleace, the Flickr-Enabled Automatic Changer for Everyone, is a free
wallpaper changer that retrieves pictures from Flickr based on topics
of your choice.

System Requirements

* Windows 95/98/ME/2000/XP/Vista
* an Internet connection

Features

Fleace is easy on the eye

* Runs automatically at startup, then terminates. Most other
wallpaper changers hang around in your system tray, taking up valuable
resources.
* Chooses a random image from the most interesting Flickr pictures
containing any of the tags you specify. These can be topics as diverse
as Paris, rainbow and kitten.
* Select whether you want pictures to be stretched or centred on
your desktop.
* Preview window shows what the wallpaper will look like, and gives
the opportunity to select another, or cancel the change altogether.
* You can set for how long the preview window is visible, down to 0
seconds to run completely invisibly.
* No program installation required

NOTE; Although Flickr supports JPEG, GIF & PNG, Fleace currently only
supports JPEG because of its overwhelming popularity. If these other
image types appear more often I shall reconsider this.