You could rotate images manually (without using ImageDataGenerator
) and save it to disk.
That way you would know which images you have rotated - so you would know which images have changed the class.
After it, when using ImageDataGenerator
, you need to set rotation_range
to small value in order to be sure that it won't change the classes of images.
Examples how to rotate image manually can be found here: https://stackoverflow.com/a/43864937/5997950