I have used your dataset to train my model, however, during the training, I got some errors related to some files, PIL.Image wasn't able to open some files, after some investigations, I found out that the file utility identify them as RIFF files, so I deleted every RIFF file and it works fine after that.
If anyone is going through this issue, here is a dataset which should work for you: https://www.kaggle.com/youben/flowers102species
I have used your dataset to train my model, however, during the training, I got some errors related to some files, PIL.Image wasn't able to open some files, after some investigations, I found out that the file utility identify them as RIFF files, so I deleted every RIFF file and it works fine after that. If anyone is going through this issue, here is a dataset which should work for you: https://www.kaggle.com/youben/flowers102species