Ryan Dezember:

Real-estate listing photos have always accentuated the positive, but computer-generated imagery of the sort Hollywood uses has now become so cheap and prolific that home sellers are taking out walls, removing ugly paneling and even adding digital swimming pools.

At the same time, photos are more important than ever: Nearly every home search begins online and deals are often struck without in-person showings, particularly among investors who are putting photos through their own algorithms to price homes as they make an unprecedented move into the U.S. housing market.

The technology allows sellers to green browned lawns, stage rooms with virtual furniture like digital dollhouses and even perform full-blown HGTV-style makeovers with clicks of a mouse.

The hazards to buyers range from disappointment when they arrive for in-person showings to blown renovation budgets. That could prove an especially thorny issue for investors, who may need to retrain computer models they use to comb through listings for houses that are good candidates to turn into rentals or flips.

Risks associated with doctored listing photos could spread beyond sight-unseen buyers. Federal rule makers are considering a proposal to open up more of the home-appraisal business to computers that generate property values partly by scraping online listing photos to gauge condition and finishes.

Redfin Corp. , the discount online real-estate broker, said that 20% of 1,463 recent home buyers it surveyed in May said they had made offers on houses they had never visited. In 2017, when the market was hotter, as many as 35% of the individuals who responded to a similar study said they had made offers sight unseen, Redfin says.