Two quick and dirty
Mac apps to resize images
One of these works on PowerPC. The other works on newer Intel Macs.
Directions: To run the app, just drop as many files as you want to resize on it. It will ask you for a dimension (in pixels). This is the dimension for the largest side of the image. The script will then create a folder on your Desktop called Cafe-TEMP and will copy the images there, resize them, and rename them Cafe1.xxx, Cafe2.xxx, etc.
As long as you choose you longest size to match those for the classified numbers, you should have no problem. Then again, I didn't test this with every file type, so your mileage may vary.
Zip file for PowerPC Macs
Zip file for Intel Macs