Yep. People often suggest attacking Touma by, for instance, throwing something at him with superstregth - the object is real, so it should get past his Image Breaker. But Touma has on several occations blocked Railgun's railgun, which is just a normal metal coin thrown very fast by Mikoto's electrokinesis, which is basicly the same thing, and he's repeatedly stopped it cold. That's basicly the same thing.
If, at any point, something supernatual was involved, Touma can make it nothing more then a meaningless illusion.