edit: oh, I see the confusion. People misunderstand what Google image search is, how it works, and are blaming Pinterest for Google's ineptitude.
Do they? They advertise images in their search results that you aren't allowed to see when you follow the link. It's some of the most paradigmatic black-hat behavior there is.
It may well be the case that this is Google's fault and they are a malicious actor here as well as Pinterest, but Pinterest is blatantly malicious and does not draw within the lines.
Anyway plenty of bad behavior to go around. Both Pinterest or Google could probably solve the issue with better engineering. I put a bit more responsibility on Pinterest, but I'm not giving Google a total pass here either.
[1] https://en.wikipedia.org/wiki/Cloaking
[2] https://developers.google.com/search/docs/advanced/guideline...