Image data augmentation is a method that can be used to artificially expand the size of a training dataset by creating modified versions of images in the dataset. However, training deep learning neural network models on more data can result in more skillful models, and the augmentation techniques can create variations of the images that can improve the ability of the fit models to generalize what they have learned to new images. And, the Keras deep learning neural network library provides the capability to fit models using image data augmentation via the ImageDataGenerator class.