It's not slagging off to say that that much bright paint will put people off. That's days worth of work and multiple coats of paint to cover all that. It's making the house look smaller as well. If you had two similar houses and one had neutral walls and one didn't, which one are you more drawn to?
If it's not that big a deal for a buyer to paint over it, then op can do it and get the photos done again.
With that garden at that price, the house needs a hand. Or she could drop the price.