Why doesn't the Firebase Storage UI ever display the thumbnail of my uploaded image?

Question

So I am trying to upload my data to firebase using python. Although my data is being pushed to the cloud and it's an image file of .png format. When I view my data in the cloud, it keeps on loading but never actually shows up. Although the size is identical to the size of the local image file. But I don't understand why It never displays the image. This wait bar keeps rotating.

Here's my code from the server-side (Python Code).

import firebase
from google.cloud import storage
from google.cloud.storage import client
import cv2
import firebase_admin
from firebase_admin import credentials
from firebase_admin import storage
cred = credentials.Certificate('certificate.json')
firebase_admin.initialize_app(cred, {
    'storageBucket': 'test-cd462.appspot.com'
})

bucket = storage.bucket()
image_data=cv2.imread('1.png')
imageBlob = bucket.blob('Images.png')
blob.upload_from_string(
        image_data,
        content_type='image/png'
    )
print(imageBlob)

Here's the screenshot of what I am getting in my firebase window:

Please help me and let me know where have I gone wrong. Thanks in advance!