A: That’s right. It’s a characteristic of Android, the Droid’s operating system made by Google, and it’s something I noted as a weakness when I reviewed the first Android phone over a year ago.

Even though the Droid comes with 16 gigabytes of memory, in the form of a removable card, apps can’t be stored on this memory card. They must be stored in a special area of internal memory, which in the case of the Droid totals only a measly 256 megabytes, about a fourth of one gigabyte. The memory card is reserved instead for things like documents, music, videos and pictures. That limits the total number of apps the phone can hold at any one time.

Google says the amount of internal memory allotted for apps is up to the hardware makers, and notes that the Droid has twice as much as the original Android phone. It also says that makers of complex apps that use things like graphics that are ancillary to the core app itself could theoretically offload these files to the memory cards.

But users of Apple’s competing iPhone can devote nearly all of its 16 gigabytes of memory to storing third-party apps, allowing many more apps to be stored on the phone.

I have all my data (addresses, calendar, notes) stored on my Palm Zire. I’d like to get an iPod Touch, but can’t figure out how to transfer the Palm calendar. Can you help? Or, do you know of any other “smart” handheld that will allow me to import my Palm data and give me Internet/email access?

A: There are various workarounds for doing the transfer to an iPod Touch, but, since you ask, there is another smart phone with great Internet capabilities that comes with a way to do it simply and directly: the Palm Pre. It’s based on a new and different operating system than your Zire is, called webOS, and is designed to sync with wireless contact and calendar sources rather than desktop programs.

But Palm has developed a one-time, one-way utility for transferring data from desktop software used by an older Palm to one of the wireless calendar and contact services with which the Pre was designed to sync. More information is at: http://bit.ly/2ivFI.

I want to buy a new computer and I really like the new iMac with the 27″ screen. I am 72 years old, which is one of the reasons I want the larger screen. Please tell me if you think my buying this iMac is a good idea. Is there some negative aspect of the iMac that I should be aware of?

A: I gave the new iMac with the huge screen a positive review, so I obviously think it’s a good computer. But, if by mentioning your age you mean to imply that you have vision issues, you should be aware that the new iMac’s screen isn’t just physically large, but is high resolution.

That allows it to pack a lot more content onto the screen, but, depending on what program you’re using, it can make the text small. Word processors, email programs and Web browsers usually allow you to enlarge text, but not all programs do.

The Mac itself has a system-wide zooming feature, but that makes some tasks harder to work with. I recommend you go to a store and play with the big iMac for a while to make sure you feel comfortable with its screen resolution.

You can find Mossberg’s Mailbox, and my other columns, online for free at the All Things Digital Web site, http://walt.allthingsd.com.

According to the CTIA, there are more than 246 million wireless data-capable devices at large in the U.S. today. Of these, 40 million are smart phones or PDAs, and more than 10 million are laptops. Little wonder that wireless data service revenue rose 31 percent to more than $19.4 billion in the first six months of 2009.

Revenue will no doubt continue that trend in the months ahead as wireless devices become more ubiquitous. Wireless carriers, then, would be wise to put some of their windfall toward building out their networks to cope with future demand lest they end up the butt of a joke in a rival’s advertisement.

Consider these remarks from Federal Communications Commission Chairman Julius Genachowski, spoken Wednesday at the CTIA wireless industry convention in San Diego: “We are fast entering a world where mass-market mobile devices consume thousands of megabytes each month. So we must ask: what happens when every mobile user has an iPhone, a Palm Pre, a BlackBerry Tour, or whatever the next device is? What happens when we quadruple the number of subscribers with mobile broadband on their laptops or netbooks? The short answer: We will need a lot more spectrum. The biggest threat to the future of mobile in America is the looming spectrum crisis.”

But keeping those types of digital-photo frames up-to-date with new pictures demands more technical skill than many parents and grandparents are likely to have. It requires, for example, rudimentary knowledge of how to configure a home Wi-Fi network or shuttle storage cards between a frame and a digital camera. Still, digital frames are a great way to keep generations in touch with, say, a far-flung child’s latest ballet recital or a football game.

Just in time for the holidays, the wireless carrier T-Mobile is selling a digital-photo frame that makes it easy to set up and to keep fresh. While I found the Cameo excels in its simplicity, it comes with a number of annoying drawbacks and a pricing model that will limit its appeal. It sells for a reasonable $99.99 in T-Mobile stores, but carries a hefty $9.99 monthly fee.

Still, Cameo is an exciting first edition of a product.

First, its strengths. The picture frame is as easy to operate as a cellphone, containing some of the same technical innards of a wireless handset. And each Cameo has a unique phone number, just like a cellphone, that lets anyone who knows the number to “dial” it up — sending messages containing digital photographs instead of voice calls.

Setting up Cameo is as easy as taking it out of a box, screwing a stick into the back to prop up the frame and plugging it into an electrical outlet. The Cameo has a seven-inch color display and one of the more attractive borders I’ve seen on a digital photo frame: imitation black leather with white stitching.

Users themselves can manually load images onto the frame from a PC by connecting it through a USB cable or by inserting a miniature storage card from a digital camera.

Cameo can receive pictures wirelessly two ways. The owner of the frame hands out the Cameo’s phone number to friends and family members, who then send pictures to the frame that were taken with the cameras standard on most modern cellphones. This method uses MMS, or multimedia messaging service, a communications standard normally used to share pictures and other media between cellphones.

Cameo owners also can give out an email address for their picture frames that is based on their Cameo’s phone number, allowing people to email images that they’ve downloaded to their computers from digital cameras.

The first time the frame receives a picture from an email address or phone number, Cameo asks the frame owner to push a button on the back of the frame to place the sender on an approved list. After that, all images from the approved source appear automatically on the frame — a method that at least keeps random people’s photos from popping up in grandma’s living room.

There’s a wonderful unpredictability to how Cameo works. Imagine all of the kids and grandkids in a sprawling family room in different locations being able to send snapshots to each other. This is possible now with photo-sharing sites like Flickr, but those typically require going to a Web site. Images on a Cameo just show up without warning on your kitchen countertop, living room or office desk.

I handed out my Cameo number to some colleagues and was delighted when their cameraphone pictures began trickling into my frame, including a shot of the New York neighborhood in which one of them lives, and an image of another colleague ice skating.

The Cameo’s screen, featuring 720×480 pixels, isn’t the highest-resolution digital photo frame on the market, but the pictures looked fine to me. You can do a slide show for any number of images, chose a fade-out or other transition, change the order of the photos and alter the display speed — holding a single image for up to an hour.

Unfortunately, the frame has a skimpy 64 megabytes of memory, and storage capacity isn’t expandable. There is enough room for only about 200 photos at maximum size. Once it’s full, you have to make room by manually deleting photos.

Another problem is that the frame currently is available only to existing T-Mobile cellular subscribers.

By far, the biggest turnoff is the monthly fee for the cellular service that delivers the pictures to the frame. There’s no limit on how many pictures can be sent to a Cameo under T-Mobile’s cellular plan, but $120 a year is a steep price.

The carrier says it will consider other pricing options in the future. Until it does, it’s going to be tough for most people to buy the Cameo, even for a beloved family member.

Walt Mossberg is on vacation.

Write to Nick Wingfield at nick.wingfield@wsj.com