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The publication bases its story on an unidentified source "familiar with the matter" - as well as the fact the startup's website is now owned by an Amazon subsidiary.
If you visit the website of $4 - the company Amazon has apparently acquired - now, you're greeted by by a short message saying it "is no longer taking new customers. Thank you very much for your interest and support. But we're up to new/exciting things."
But last year, $4 "revolutionary image recognition technology helps computers to see like human beings."
Using neural networking AI, its software worked out what was in photos, and was implemented in a consumer-facing app called PhotoTime, and as well as an API called $4.
This kind of photo-recognition tech is increasingly finding its way into consumer apps. Google's Photos app automatically detects what's in your photos and categorises them appropriately, and just this week $4 that would detect the contents of photos using AI to help blind people use its social network.
Amazon, like Facebook and Google, is putting increasing focus on AI. In March, $4.
Amazon did not immediately respond to a request for comment.