Preview is definitely one of the unsung applications of the Mac OS X system, a simple application that on first blush looks like it's just a photo and graphic display application, but is really quite a bit more powerful.

You're not alone, by the way, I also use Preview to help me organize screen shots for articles I write on this very blog. And because of that, I can show you exactly how to sort your multi-image sidebar by name, date, size, path, kind of file or keyword.

Remember, Preview can display quite a bit more than just images, too. You can hand it PDF files, audio, movies, and quite a bit more. Very helpful!

So here's a typical Preview view with a bunch of images opened (which you can do by selecting a group and then opening them all at once):

You can see that I have six images loaded into Preview, and by default, they're sorted in name order. Not what we want.

To change the ordering, you need to click on the little triangle adjacent to the gear on the lower right. It pops up a menu with Sort By... and there you can see exactly what you want:

Choose "Date" and, voila! You have a Preview multi-image view that has the thumbnails sorted by creation date!