The point, of course, is that memory cards are designed for temporary storage inside the camera. Once the card is full, your photos desperately want to be transferred to some larger, safer, more permanent home.

Of course, for most people, that home is a computer. But hauling a laptop around on your sightseeing trips isn't always practical. Besides, it's like wearing a T-shirt that says, "I'm a Tourist--Rob Me."

You could buy a whole bunch of memory cards, but that gets expensive. You could also buy a portable CD recorder (about $275) that burns photos right from the card, but that's bulky and slow.

But hey, this is the era of tiny hard drives. Why can't someone invent a handheld gadget that slurps photos off a memory card and onto a hard drive, so you can wipe the card clean and get back to shooting?

Fortunately, several someones have invented just that: Gadgets variously called photo vaults, photo wallets, digital photo viewers and mobile media hard drives. Or, if you have an iPod music player, you can turn it into a photo vault, too, using adapters sold by Belkin and Apple Computer, which has just introduced something called the iPod Photo Connector.

The dedicated photo vaults (from Epson, Archos, Nikon, SmartDisk, Jobo and others) have several advantages over the iPod adapters. First, they have much bigger screens, making it easy to show your pictures to your friends and delete the losers. (The photos, that is, not the friends.)

Second, they can also play music and sometimes movies, although in a limited number of file formats; for example, most can't play copy-protected songs you buy off the Internet. (When connected to a Mac or PC through a USB cable, these devices act like external hard drives--that's how you load music and movies--and memory-card readers.)

Third, you can hook up any of these players to a television, the better to elicit oohs and aahs from your entourage.

Finally, these devices have their own battery packs and memory-card slots. When you transfer the pictures, in other words, you're not draining your camera's battery (as you would when connecting it to a laptop). That's important because when you're out and about, camera-battery juice is a precious resource.

Choice of bells, whistles
The photo vaults in this roundup--the Epson P-2000, Jobo GigaVu Pro, Archos AV420 and SmartDisk FlashTrax--present a wide range of choice in size, shape, bells and whistles.

(Nikon, whose compact Coolwalker MSV-01 is intended for use with Nikon cameras, declined to provide a unit for evaluation. This roundup also omits screenless models, which deprive you of half the fun.)

Most have a slot only for Compact Flash cards. If your camera uses a smaller type, you're expected to provide your own card adapter. Only the Epson P-2000 also offers a slot for SD cards.

Nor is that the only virtue of the sleek black Epson ($500 online). The size, brightness and clarity of its 3.8-inch screen blows its competition off the equipment rack. Thanks to its supercrisp 640 pixels by 480 pixels (four times the resolution of its rivals), photos look like glossy drugstore prints. Photo transfer is fast: just under two minutes for a 256MB memory card filled with 103 pictures.

This is also the only photo vault that's serious about slide shows: You can choose background music, and you can opt for gentle animated panning and cross-dissolving effects that lend a sweet, soft-focus, Hallmark Hall of Fame feeling.

But at 5.8 inches by 3.3 inches by 1.2 inches, the Epson is not what you'd call petite. If you'd prefer something more compact, investigate the genuinely pocketable Archos AV420 (4.9 inches by 3.1 inche by 0.8 inches).

Now, the Archos ($450) was never intended to be a photo wallet; it began life as a pocket multimedia machine, capable of, for example, recording television shows (even unattended) so you can watch them on the road. But because it's so slim, so capacious (up to 100GB) and fast (1 minute 40 seconds to transfer

that 256MB card), photographers have begun adopting it for photo-offloading use.

It's nowhere near as good as the Epson at that task, though. The 3.5-inch screen is only 320 pixels by 240 pixels; there's no dedicated Transfer Photos command or button; it can't display RAW files of any type; and you don't get any kind of progress indicator or thumbnails of incoming photos while you're importing. But did I mention that it's small?

Small is not the word for the bulbous Jobo GigaVu Pro (5.7 inches by 4.2 inches by 1.5 inches). This device seems aimed at more serious photographers, both in its price ($500 for the 40GB model), its handling of advanced photo formats like RAW and TIFF, its speed (3:09 for the 256MB test) and, alas, its confusing operating system. (Why, for example, don't the unavailable options grow dim or disappear, as on any self-respecting operating system?) The protective lid, which you can snap underneath when you're using the thing, is a nice touch, but most people would be happier with the Epson.

SmartDisk's FlashTrax protects its own screen, too: You flip it up to use it, as though it's the Terminator's makeup compact. This device is remarkably devoted to its task: Without knowing a thing about the Windows-esque filing system, you insert your memory card, press the Copy button, and the deed is done. Other grace notes include a swappable battery, and the ability to play back your digital camera's movies.

The FlashTrax is also notable for its price: $280 for the 20GB model, or $350 for 40GB (both prices reflect a $50 rebate good through April 30). Note, however, that much of the economy comes from the inclusion of the homeliest, most washed-out screen of the lot.

Now, if you have an iPod music player, you're already carrying around a 10GB or 60GB hard drive, and in a unit that's much smaller than any standalone photo vault.

Battery draining
Belkin offers two camera-to-iPod transfer adapters. The Digital Camera Link (about $56 online) is a white plastic box that connects your camera (through its USB cable) directly to the iPod. The transfer is slow (6:45 for the 256MB card), the device is bulky (the size of the iPod itself), it drains your camera's battery, and it eats up its own AA batteries like there's no tomorrow. And on black-and-white iPods, you don't actually see the photos; each transfer is identified on the iPod screen only by name, date, file sizes and number of pictures.

The Belkin Media Reader ($100) is another, even bigger white plastic box (3.4 inches by 4 inches by 0.8 inches), this time loaded with four AAA batteries. The transfer is even slower - over 9 minutes for that 256MB card test. But this time, you don't drain your camera's battery because you put the memory card directly into the Belkin.

In both cases, your Mac or PC imports the photos from the iPod exactly as you would from a digital camera.

Life is much sweeter if you have Apple's iPod Photo ($350 for the 30GB model), which has a color screen. In that case, you can use Apple's new iPod Photo Connector ($30), a tiny, white plastic doohickey that snaps directly onto the iPod. When you connect your camera's USB cable to it, the iPod cheerfully offers to import the photos. During the importing process, you see each photo as it comes in, along with helpful progress indicators and a choice of "Stop and Save" and "Cancel" buttons.

The charms of this solution, of course, include its extreme tininess, very low cost and compatibility with those big RAW files and digital movies (which the iPod can import but not display).

The drawbacks are considerable, though. The transfer is very slow (10.5 minutes for that 256MB card), and the iPod's battery takes quite a hit. Note, too, that although you can view the imported photos on the screen, the iPod Photo can't display them on a television--one of the device's best features--until you've returned home and synchronized them with your Mac or PC, which puts them back on the iPod in the proper format.

Thanks to an annoying little thing called physics, you can't have fast, cheap, small body, big hard drive and big screen all in one gadget.

If you prefer small and capacious, though, an iPod Photo with the little adapter represents the tiniest photo-wallet system you can buy--and, oh yeah, you get a really great music player at no extra charge. For savings and ruggedness, choose the SmartDisk FlashTrax. If you prefer a big screen and speed, you'll be thrilled by the spectacular display on the Epson P-2000. Any way you go, the next time you're traveling, you'll sleep better knowing that your photos are safely snuggled into a little digital hotel room of their very own.