At the Betty Cuningham gallery on the Lower East Side recently, I noticed an arresting painting: It showed a nude woman curled against a window, asleep, with the old New Yorker Hotel and Empire State Building in view and a fish above her, hanging or floating. I opened a smartphone app called Magnus, snapped a quick picture, and clicked “Use.” Seconds later, I got that addictive, satisfying click. The app had found a match.

The painting was by Philip Pearlstein, according to the app, known for reinvigorating the tradition of realist figure painting . It was titled “Model With Empire State Building.” dated 1992, measured 72 inches by 60 inches, and was for sale for $300,000. In 2010, it had sold for $170,500 at Sotheby’s in New York, the app told me. Magnus then slotted this information into a folder marked “My Art” for digital safekeeping — and future looking.

Magnus is part of a wave of smartphone apps trying to catalog the physical world as a way of providing instantaneous information about songs or clothes or plants or paintings. First came Shazam, an app that allows users to record a few seconds of a song and instantly identifies it. Shazam’s wild success — it boasts more than a billion downloads and 20 million uses daily, and was purchased by Apple for a reported $400 million last year — has spawned endless imitations. There is Shazam for plants or Shazam for clothes and now, Shazam, for art.

The art-oriented apps harness image recognition technology, each with a particular twist. Magnus has built a database of more than 10 million images of art, mostly crowdsourced, and aims to help prospective art buyers navigate the notoriously information-lite arena of galleries and fairs.