Viewfinder is a desktop app that makes finding and downloading photos from Flickr much faster and easier. The app's well-designed, streamlined interface is centered, fittingly, around Flickr search results: you just type your terms into a search bar (specify text or tags in a drop-down menu), and the main window is quickly populated by results that you can preview, download, or open in Flickr using your browser. What makes this app so helpful is its ability to apply filters to your results; so, for example, you can look only at photos licensed under Creative Commons (more likely to be legal for noncommercial use), or you can sort by minimum size (up to 1,500 pixels) or by Flickr's "most interesting" property.
Viewfinder also makes it easy to set your desktop to a particular photo, or to download and export to Keynote, with a single click. Unfortunately, the demo version only allows two downloads per launch, and it priggishly penalizes you by delaying even those two downloads by 30 seconds. Viewfinder is an effective and attractive app, but given its price (set to increase even further with 1.1) and that much of the functionality is available via other Flickr-enhancing Web sites, it's only going to be of interest to heavy Flickr users.