if args.dataset == 'cifar10':
        train_dataset = datasets.CIFAR10(
            root=args.data_dir,
            train=True,
            transform=transforms.Compose([
                transforms.RandomHorizontalFlip(),
                transforms.RandomCrop(size=32, padding=4),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.4914, 0.4822, 0.4465],
                                     std=[0.2023, 0.1994, 0.2010]),
            ]), download=True)
        val_dataset = datasets.CIFAR10(
            root=args.data_dir,
            train=False, 
            transform=transforms.Compose([
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.4914, 0.4822, 0.4465],
                                     std=[0.2023, 0.1994, 0.2010]),
            ]), download=True)
    else:
        train_dataset = datasets.ImageFolder(
            root=args.data_dir, 
            transform=transforms.Compose([
                transforms.RandomHorizontalFlip(),
                transforms.Resize(224),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.485, 0.456, 0.406],
                                         std=[0.229, 0.224, 0.225])
            ]))
        val_dataset = datasets.ImageFolder(
            root=args.data_dir, 
            transform=transforms.Compose([
                transforms.Resize(224),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.485, 0.456, 0.406],
                                         std=[0.229, 0.224, 0.225])
            ]))  

what does the transform do ?
I mean the RandomCrop
transforms.RandomCrop could not be applied to VOC2007 dataset which consists of images of different dimensions.