OK, I’ll be the first one to let the cat out of the bag. Spotlight is broken. The review at ars technica pointed to reasons why.
Would you like a nice example. I have a cron job that downloads pictures from my favourite alt.binary.pictures newsgroup and saves them into a folder. If you do a search in that folder for all images with pixel height less than 400 or pixel height greater than 400 you get every picture in the folder. This despite the fact that in the Spotlight window it will display the preview and below it the correct size of the image. Duh!
It also suffers a little from speed issues on my Powerbook. It may speed up when it has bedded in. You don’t mind the speed for complex stuff, only the simple searches. For the simple ones I’m still using Quicksilver.
By the way, I ran the folder full of files through Graphic Converter’s ‘Create Icon/Preview’ routine and it gave the files the right metadata so Spotlight searched them correctly.
Once I discovered that I tried to write a folder action using Automator. Now that’s another joy, debugging Automator workflows. Stll haven’t got it working right. the problem isn’t with Automator but with Graphic Converter, I suspect it is due to me using an unregistered version – I should buy the update but I resent updating a piece of software for the third time in as many years.