Usingmac.com had a useful tip: How to resize multiple images using Preview. I tried it, it does work on Leopard. This seems like a great way to create a bunch of thumbnails. Be careful, though, when you save the resized images. It overwrites them. I copied the images I wanted to resize to a new folder, then resized them. Keeps my original images as is.
- Open images to be resized in Preview
- Select images you want to resize.
- On the Preview menu Tools -> Adjust size.
- File -> Save All The images are overwritten.
Dagny's Desk 
Andrew said:
Just wanted to say, thanks for the tip. I’ve always resized one by one in Preview because I didn’t know any better. This time I had 40 images and was looking for a shortcut. Google sent me to you and it worked perfectly in 10.5.3. 🙂
name said:
Good day!,
Arnold68 said:
It has pedagogical purpose to enable students to think critically about the issue of evaluation and rubrics, and therefore to think critically about their own submissions. ,