The present invention relates to a method for forming images which comprises imagewise exposing a photopolymerizable image-forming material comprising a substrate provided thereon with an image-recording layer which comprises a specific photopolymerization initiator system, a polymerizable compound carrying at least one ethylenically unsaturated group and a binder polymer and then developing the imagewise exposed material with a developer containing at least one carbonate and at least one hydrogen carbonate and a specific surfactant in an amount ranging from 1.0 to 10% by weight, and having a specific pH and a specific electrical conductivity. The image-forming method permits the achievement of a sufficient developing ability even at a relatively low pH at which the image-forming material is not damaged so much and the preparation of a printing plate having good printing durability.