Why are my Mac thumbnail icons so fuzzy?

This was my mistake, I think. I suggest that you can use GraphicConverter to easily create thumbnail icons from your pictures so that when you view the folder in the Finder on Mac OS X that you'll see the images, not a generic JPEG icon, but I didn't mention the ideal settings for creating these icons.

GraphicConverter is a great program that I use every day, but I have to admit, it's rather complicated, and nowhere more so than in its preferences. To help you out, let me show you how to set the preferences to get the most attractive possible thumbnails for your photographs and pictures!

Start up GraphicConverter, then choose GraphicConverter --> Preferences. You'll see this:

You can make some changes to your settings for digital cameras (and, yes, GC can happily auto-import photos from your camera when hooked up, if you'd like) but let's stay focused here!

Click on Custom Icon under Save, and you'll see:

Here's where you'll want to make sure that you have the same settings I show, especially Add thumbnail icon (128x128 pixel) to ensure that you have attractive icons in the Finder. If you don't like the little folded-down corner on the icons, uncheck "add dog ear" too.

While we're here, click on General under the Save category and make sure that you'll also create custom icons any time you work on a file and save it or save a new version:

You can see my recommended settings in the figure above.

One final check: GraphicConverter is smart enough to skip creating a new preview and thumbnail icon if one's already created, but that can be a bit frustrating if you're trying to fix things because, for example, you didn't have the larger thumbnails created when you first ran this process. To ensure it'll ignore existing icons and always create new ones when you do a batch conversion, go to Convert and choose Icon/Preview and make sure that the value there is unchecked:

That should get everything working properly for you and good luck!