The previous discussion describes copying photos only in one direction: Computer→iPhone. But here's one of those rare instances when you can actually create data on the iPhone so that you can later transfer it to the computer: photos you take with the iPhone's own camera. You can rest easy, knowing that they can be copied back to your computer for safekeeping, with only one click.
Now, it's important to understand that iTunes is not involved in this process. It doesn't know anything about photos coming from the iPhone; its job is just to copy pictures to the iPhone.
So what's handling the iPhone→computer transfer? Your operating system. It sees the iPhone as though it's a digital camera, and suggests importing them just as it would from a camera's memory card.
Here's how it goes: put the iPhone into its cradle. What you'll see is probably something like this:
On the Macintosh, iPhoto opens. This free photo-organizing/editing software comes on every Mac. Shortly after it notices that the iPhone is on the premises, it goes into Import mode.
Turn on "Delete photos after importing" if you'd like the iPhone's cameraphone memory cleared out after the transfer.
Either way, click Import on the Mac screen to begin the transfer.
In Windows. When you attach a camera (or an iPhone), a dialog box pops up that asks how you want them handled. It lists any photo-management program you might have installed (Picasa, Photoshop Elements, Photoshop Album, and so on), as well ...