My model's output tensors dont't change given by diffent images

I use a loop instead of data loader to read images and use model to predict them, however, my model always ouputs the same tensor. I 'm sure the input images are diffrent, and comverted to tensors with proper shape, below are the key codes, can anyone figure out the problem?

Classes = os.listdir(valdir)
for Class in Classes:
imgs = os.listdir(os.path.join(valdir, Class))

    for img in imgs:
        total += 1

        imgPath = os.path.join(valdir, Class, img)
        im = fetchImage(imgPath, trans)
        im = im.cuda(0)
        output = model(im)

I’m sorry, I’ve loaded the worry model