How to add Gaussian noise to the pictures in ImageDatastore

Thank you for guiding me

Is my understanding of these codes correct?

Assuming that variable Train contained one hundred images

aug = imageDataAugmenter('RandRotation',[0 90],'RandScale',[1.1 1.3]);
auimds = augmentedImageDatastore([224 224 1],Train,'ColorPreprocessing','rgb2gray','DataAugmentation',aug);

After executing these codes

100 original images

100 images that have been circulated

100 images with different scale

And in total I will have 300 images

It is true??

I'm going to add noise to the original images

In other words, I have 100 photos to which Gaussian noise has been applied

How do I add these 100 noise images to 300 images ??

To have 400 images in the end