There appears to be a problem with IOS 8 software for the iPad or iPhone that affects photo uploads.
We would advise that you upgrade to the latest IOS 12.1
Here is a link that confirms others are having the same issue using IOS 8
https://discussions.apple.com/thread/6544026
The only workaround to get iPad images you have taken on your iPad uploaded into your account is to save the image and then email to yourself as an attachment.
You can then pick this up on your PC and save it to your desktop then upload into your account.