Fragmentation processes of SO2 following excitation of the six main O 1s pre-edge resonances, as well as above the ionization threshold and below the resonances, are studied using a position-sensitive time-of-flight ion imaging detector, and the associated dissociation branching ratios and break-up dynamics are determined. In order to distinguish between the O+ and S2+ fragments of equal mass-to-charge ratio, the measurements have been performed with the isotopically enriched S18O2 sample. By analysis of the complete set of the fragment momentum vectors, the β values for the fragments originating from the SO+ + O+ break-up and the kinetic energy release for fragmentation channels of both SO22+ and SO23+ parent ions are determined. We also present results on the three-body break-up dynamics.