Icing on the cake, or gilding the lily?

That’s the big question regarding Apple’s new iPod Photo, and my answer is yes to both.

Yes, icing on the cake, because the iPod Photo takes what is already the best portable digital music player on the market and makes it better – adding a color screen for viewing pictures.

Yes, gilding the lily, because the iPod Photo is $100 more expensive than an equivalent non-photo iPod and the screen is too small for appreciating many photographs.

Whether you want the iPod Photo (www.apple.com/ipodphoto) depends, then, on how much money you’re willing to spend and the value you place on looking at images of friends and family on a two-inch screen that’s smaller than what you’d find on some digital cameras.

There are two models of iPod Photo, due to reach stores about now: a 40-gigabyte one for $499, or a 60-GB version for $599. Remarkably, the weight ticks up only slightly to 6.4 ounces from the classic iPod, while maximum battery life jumps to 15 hours when playing music from 12 hours on the classic. Battery life drops to five hours when viewing photo slide shows.

I borrowed the 60-GB model from Apple and was only somewhat impressed.

The screen is the same size as the dim monochrome display on what I call the iPod classic, just 1½ inches wide by 1¼ inches high. While the iPod Photo’s backlit screen is bright and sharp, making it easier to navigate through your music library, it’s just too small for comfortably viewing anything other than close-up pictures.

I loaded up photos from several of my annual vacations in Hawaii. Shots of family members were fun to share, but panoramic shots of sand and sea became indistinct blurs.

You can create slide shows accompanied by the iPod’s music, either advancing the images manually or at a speed you control, but only one person can listen at a time through headphones unless you cart along external speakers. You can also flip through the pictures at lightning speed by running your finger around the iPod’s scroll wheel.

Apple does offer one alternative: You can connect the iPod Photo to a television to play slide shows with music, using a cable included in the box.

My Hawaii pictures looked good on TV, although I couldn’t sit on the sofa while manually stepping through the pictures, because the cable was too short. Existing wireless remotes for the iPod won’t work with slide shows, although I expect someone will fill that gap quickly.

My guess is that many iPod Photo buyers will play around with pictures for a few days after getting the device, then shift to using their iPods for what they do best – playing music.

Also, uncommon for Apple products, I encountered some confusion and error messages when installing the iPod Photo software on a Windows XP computer. Everything worked in the end, but only after a few white-knuckle moments. The iPod Photo was also very slow to connect; after plugging it into my computer via FireWire, it took just over a minute to open the iTunes software and start synchronizing. An Apple representative said the company hasn’t heard widespread reports of either problem.

Whatever you think of the iPod Photo, Apple is in the happy position of competing with itself.

The iPod family is so far ahead of the competition in ease of use and elegant design that it’s become a technology ecosystem, supporting a long list of companies that make all kinds of clever accessories.

If you want to buy a digital music player this season, in other words, you shouldn’t consider anything other than an iPod.

I overcame some earlier skepticism and became a convert myself in February, when I purchased a 15-gigabyte iPod for $299. I’ve loaded the iPod with about 180 albums, everything from Mozart and the Rolling Stones to Thomas the Tank Engine songs for my 4-year-old daughter Sara. I also listen to many hours of audiobooks every week on the iPod, through a subscription to the steadily improving Audible service (www.audible.com).

But you still have some thinking to do when buying an iPod, because Apple is now offering three types:

_The classic iPod, now in its fourth generation. The 20-GB model is $299 and weighs 5.6 ounces; the 40-GB model is $399 and weighs 6.2 ounces. Maximum battery life is 12 hours. Available in any color you want, as long as it’s white. Hewlett-Packard also sells these two models under its own name (www.hp.com/music), with no changes in looks or performance.

_The tiny iPod mini at $249 and 3.6 ounces, with a 4-GB drive. Maximum battery life is eight hours. Available in blue, gold, green, pink and silver.

_The color-screen iPod Photo, also in white.

For most people, I believe, the best deal by far is the 20-GB classic at $299.

If you convert CDs to digital MP3 files at 128 megabits per second, the recommended rate for near-CD-quality sound, or buy music from Apple’s online iTunes store, the tracks take up about 1 megabyte per minute of playing time. The average album is about 50 MB, so the 20-GB iPod will hold about 400 CDs. That’s more than enough for anyone but extreme music fans; for them, there’s the 40-GB classic.

The iPod mini is for those who want to get physical – it’s small enough to strap on your arm while jogging or mountain biking or sky diving – or who just want to make a fashion statement with its bright colors. The trade-off is lack of capacity; you can’t carry around your entire music collection, unless it’s under 80 CDs.

Two footnotes. First, any iPod you choose requires a newer computer. You’ll need Windows 2000 or Windows XP, with either USB 2.0 or FireWire connectors; or a Macintosh running OS X. Buying music from Apple’s outstanding iTunes Music Store is impractical without broadband.

Second, there’s an intriguing alternative for photo hobbyists in need of a mobile device to display pictures. The new Epson P-2000 (www.epson.com) has similar specs to the iPod Photo: a 40-GB drive for $499, capable of playing MP3 music files and showing photos. The difference is screen size: the P-2000’s 3.8-inch color LCD is 3½ times larger than the iPod. On the other hand, the P-2000 is much bigger and much heavier at 16 ounces, so you’re less likely to carry it around than an iPod.