Sounds like they are to me.
It's not explicitly stated either way, but when people talk about "image results" it seems safe to assume they are taking about Google Image Search.
With Pinterest results this sometimes happens: https://imgur.com/a/ktyNG
But not always: https://imgur.com/a/RrjJG
Notice how in the second link Pinterest is asking me to log in, even though I am clearly already logged in.
Sounds like they are to me.
It's not explicitly stated either way, but when people talk about "image results" it seems safe to assume they are taking about Google Image Search.