Wanting to quickly resize bunches of digital camera images, I found the available shareware apps a bit overkill and spendy for the task, and wondered if there was anything similar to BeOS' Tracker add-ons that would let me do the job directly from the file management interface. As mentioned in a previous hint, you can download Toolbar Scripts for OSX that integrate directly into the Finder. Lo and behold, Apple offers a free "Scale by %" script that does exactly what I needed.
Place the script in ~/Library/Scripts. In Finder, use View -> Customize Toolbar. Drag the "Scale by %" script from ~/Library/Scripts onto the toolbar. Navigate to a folder full of images you want resized, click the Scale By toolbar icon, and enter the scale factor into the dialog. Bingo - hundreds of images resized with two clicks, without opening a separate app.
Warning: The script will overwrite the original images, rather than writing out new filenames. If you want to save the original images, be sure to make a copy of the folder before beginning. It should be possible to modify the script to fix this.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20011028154150548