Thank you so very much for all your cooperation!!
Problem solved!!
Shape of the tensor which came out as [1, 50, 50] successfully became [50, 50] by first loading the image with OpenCV and transforming into PIL to modify.
As @mattdeitke and @ptrblck said, green-ish visualization of the image was a matter of option. Using plt.gray() solved the problem.

class MyDataset(Dataset):
    def __getitem__(self, idx):
        label = self.image_dataframe.iat[idx, LABEL_IDX]
        img_name = os.path.join(self.root_dir, 'data', 'load_data', self.image_dataframe.iat[idx, IMG_IDX]) 
        image = cv2.imread(img_name)
        if self.transform:
            im = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
            im2 = cv2.cvtColor(im, cv2.COLOR_RGB2GRAY)
            image = Image.fromarray(im2)
            image = self.transform(image)


trans = transforms.ToPILImage()
plt.imshow(trans(imgDataset[0][0]))
plt.gray()
plt.show()