Wow! I just learned something incredibly cool over ZOPEN-X:
via xlab: "I wasn't aware of this, but when your digital camera takes a shot, data such as time, shutter speed, aperture, focal length, and ISO are written to the file header. This information can be then examined within image editing applications such as Photoshop 7 or iPhoto."
This is awesome. It's probably obvious, but I only realized a week or so ago that JPG could hold meta data when I saw the RDF image example. I just checked and yes, all the data is in my photos I've taken with my Digital Canon Ixus/Elph. Yeah!
The reason this is so great is that I've got over 4,000 images that I've taken in the past 3 years and I've discovered the only real way to keep track of them all is by date. Trying to categorize them ("vacation to Paris") in any other way starts to become impossible ("weekend dinner at in-laws #14"). The problem is that the file modified date/created date on the image files are flaky as hell. If you touch the file in any significant way (copying from different volumes or rotating the image) you lose the date info.
It's nice to know that I have another way to find that info in unmodified files - I just tested rotating the image using Firehand and it loses the metadata still. But at least this gives me other options. I need to learn how to use Java to read/write to this meta-data section then I'll be styling.