In certain long pages, the extension might fail to reach the bottom of the page with "Whole Page Screenshot"

[terryjiang2020]

Describe the bug
For example, when making a whole page screenshot for https://www.apple.com/nz/mac-pro/, the screenshot would not reach the bottom of the screen.

It does work for most other pages, though.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://www.apple.com/nz/mac-pro/'
2. Click on 'Whole Page Screenshot'
3. Wait for the process to be finished
4. See the result

Expected behavior
A screenshot from the top to the bottom of the page.

Screenshots
If applicable, add screenshots to help explain your problem.

Somehow the image uploading does not work here.