I have two cameras in front of me: My smartphone and a Canon’s S90. And I wonder: Why isn’t there an app store for this neat compact camera?

I can download any number of third-party, post-processing photo applications to my smartphone. I can crop, filter, stitch, frame… And there will be more applications tomorrow. With my “real” camera, I’m stuck with yesterday’s features.

As the saying goes, the better camera is the one you always carry. (By the way, “Better Camera” is the name of a smartphone application…) In that sense, smartphone cameras have a major advantage, they’re always at the ready.

But…smartphones cameras have tiny sensors, tiny lenses, tiny flashes. While the technology improves with each new generation, smartphone cameras will always lag behind the resolution, speed, and depth of single-purpose compact cameras, with their better lenses and bigger sensors. And, yes, compared to even “realer” cameras such as DSLRs, the compact cousin has much to learn, but try stuffing the callipygian Nikon D3s in your pocket.

Wouldn’t it be neat to have the superior picture taking capabilities of the Canon S90 (or other competitors such as the upcoming Panasonic LX-5) and the benefits of downloadable third-party applications to perform more in-camera processing and editing, to say nothing of smartphone-like communication capabilities?

Technically, such a hybrid is easier said than done. Add the circuitry (processor, memory, communications) of a smartphone to an existing compact camera and, done poorly, you’d get a “feature-rich” monstrous contraption that does more than either donor product, but that does none of them as well. Cost would also be a challenge.

But the idea is in the air.

Years ago, enterprising geeks found a way to break into and modify Canon’s DIGIC, the camera’s on-board image processor. This has become a worldwide hacking community project called CHDK, the Canon Hack Development Kit. It covers dozens of Canon cameras and its forum discussions are available in thirteen languages, including Farsi and Finnish. Imagine what hackers would do if a good compact camera had the processing power, the UI, the development tools, and the app store of a smartphone.

The Android world might be give us hope. In China, where so many smartphones and compact cameras are made, there’s a parallel version of Android called OPhone. A product of Google’s Apache licensing model, OPhone can use Android source code and modify it at will–as long as it doesn’t call itself Android. (I’ve simplified the licensing arcana a bit but without distorting the main point of the story.)

An enterprising Chinese ODM, one the many companies that manufacture products for big brand names, could take the matter into its own hands and create a smartcamera hybrid.

This, in turn, might cause the visionary sheep at one of the better known camera makers to embrace the idea.

Would it be profitable? For a sense of proportion, digital camera sales reached about 110 million units in 2009, a 12% decrease from 2008. 2010 numbers are expected to go back to 2008 levels. These are respectable volumes. They’re less than cell phones but more than netbooks (79 million in 2009).

The idea of an app store has gained acceptance. We’ve already seen Google TV, which is pushing on beyond cable. What other consumer products could be enhanced by a lively market of downloadable apps?