Thermally imageable elements useful as on-press developable lithographic printing plate precursors are disclosed. The elements comprise a substrate and a layer of an imageable composition over the substrate. The imageable composition comprises a photothermal conversion material, particles of a polyurethane polymer, and, optionally, a water soluble polymer. The polyurethane polymer comprises urethane linkages in the main chain, but does not comprise side chain urethane groups.