Strange out of memory while loading lots of pictures before input CNN for deep learning
You should load images in batches. 480K of 224*224 sized images is too large for any machine let alone a 64GB one.

You can use image_generators from keras or tf.keras 

https://www.tensorflow.org/tutorials/load_data/images#load_using_keraspreprocessing

https://keras.io/preprocessing/image/