Tell me the better option!

Hi,
I am building my amazon aff niche site and I am stuck in a confusing situation.
One of my competitors is using images in his content which are directly hosted on amazon.

Something like this:
https://images-na.ssl-images-amazon.com/images/I/81gS9Sx0g7L._SL1500_.jpg
(He is ranking number 1 btw)

and some competitors are using usual wp uploaded images.

Now my question is, which way consumes more memory and make website slow?
First method or second method?
Which way I should do my images?
Please advise. Thanks

I would like to know this too.

Hotlinking the Amazon image is faster because their CDN is global and has unlimited resources. But Amazon can come after you for hotlinking, ban you, etc.