A study of large p_T jet photoproduction is carried out for the ep collider HERA in leading order (LO) in QCD, with emphasis on the sensitivity of the cross sections to various structure function parametrizations. Updated estimates of various jet cross sections are made using the latest parametrizations of the parton distribution functions of both the proton and photon. In particular we re-examine in detail the possibility of using jet production at HERA as a means of directly measuring the quark and, in particular, the gluon distributions of the photon.