SAN FRANCISCO, United States — Google last month quietly bought Undecidable Labs, a startup founded by a former Apple Inc. director that focused on turning online searches into purchases, according to a person familiar with the deal.

The acquisition suggests that Google, the largest unit of Alphabet Inc., is making further moves to tie its massive library of online image links with a revenue stream.

Earlier efforts around online commerce have delivered mixed results at Google. The company's mobile payments have yet to see significant pickup. Its comparison shopping service, which facilitates online purchases within search results, has growing traction with advertisers, according to external estimates.

Cathy Edwards, founder of Undecidable Labs, now oversees engineering and product development for image search at Google, a spokeswoman for the internet giant said on Monday. The representative declined to comment further.

Undecidable Labs, based in San Francisco, had raised less than $1 million in financing, according to a person with knowledge of the startup. They asked not to be identified talking about private matters.

Edwards spent two years as an engineering director at Apple, after the iPhone maker purchased her app search engine, Chomp, in 2012. She formed Undecidable Labs in early 2015. The company had yet to release a product.

Stefanie Kraus, a designer listed as an employee of the startup, described its effort on her website as creating a "purchase research tool" for online shoppers.

"By introducing a filtering system that takes `nice to have' and `ideal' into consideration, we make sure that the products are presented in a meaningful way," Kraus wrote on her website.

Li Fan, who previously led engineering efforts for Google image search, left the company in September. She moved to Pinterest, the online discovery site that some analysts see as a viable contender for e-commerce spending and search advertising dollars now flowing to Google.

By Mark Bergen and Alex Webb, with assistance from Adam Satariano.