The present study statistically examines energetic neutral atom (ENA) emission from the storm-time inner magnetosphere using measurements from the IMAGE/HENA instrument. It is found that the total image-integrated ENA energy flux is well correlated (∣c.c.∣ ~ 0.7) with the Sym-H index. However, the increase is not linear but exponential with ∣Sym-H∣, which can be attributed to the fact that the ring current moves closer to Earth as the storm becomes more intense. The oxygen (52--180 keV) energy flux increases more steeply with ∣Sym-H∣ than the hydrogen (27--60 keV and 60--119 keV) energy flux, which is consistent with the results of in situ measurements reported previously. The relative contribution of near-Earth emission to total energy flux is larger during the main phase than during the recovery phase presumably because during the main phase the ring current moves closer to Earth and ion precipitation is more intense. Interestingly, if Sym-H is the same, the ring current emission of 60--119 keV hydrogen and 52--180 keV oxygen is systematically weaker during the main phase than during the recovery phase. This can be explained if the ring current is indeed weaker during the main phase than during the recovery phase (for a given Sym-H), and its smaller contribution to Sym-H is compensated by the contribution of a more intense tail current. This idea is confirmed by the finding that the geosynchronous magnetic field is more stretched during the main phase.