I don’t know if it’s a bug or not but it’s interesting that ImageDataBunch.from_folder function cannot read images if the name of the image has a capitalized extension like “.JPG” instead of “.jpg”. I checked the root cause behind this problem and it seems like when ImageDataBunch.from_folder calls ImageClassificationDataset._folder_files function and that calls get_image_files (present in vision/data.py) which checks for a valid extension from image_extensions list (mimetypes list). This image_extensions list only have lower_case extensions mentioned which could be the potential problem.
So instead of (o.suffix in image_extensions)) check maybe the check should be (o.suffix.lower() in image_extensions)) because in my opinion it doesn’t matter if the extension is capitalized or not.
