Trains imagenet for 100 epochs by default.
This is closer to the number of steps reported in README's linked
TensorBoard runs
https://tensorboard.dev/experiment/jrvtbnlETgai0joLBXhASw
225_200 steps, batch_size=512
https://tensorboard.dev/experiment/F5rM1GGQRpKNX207i30qGQ
56_250 steps, batch_size=2048
