Yes, they will be, moving on. All joking aside, you really should know the answer to this question. No, the physical size has nothing to do with how bright a specific flashlight is going to be. If that were the case then none of the models that appeared on this list would be very bright. Remember, it is all about the lumens and the beam distance (and also the candela).
And, if a larger model is brighter than a smaller model that merely means that the aforementioned specifications are superior. Of course, it is fair to say that larger models can implement larger LED bulbs (which can make a difference in the diameter of the light).