https://www.copyrightlaws.com/copyright-and-using-google-images/
You touched on some fine points concerning the law. Its just advised to play it safe and always source. Helpful if you want to participate in key/elite contests. I would say you're doing well on your post rewards though. If I could get rewards like this on two posts a day I would be making 4 because I could live off the rewards your getting.I'm'm also not a super talented writer like you!
I was politely asked to try and keep my posting to 2 a day, but def no more than 3. If i do four or more, I will take away too much from the rewards pool in one of my groups. I show respect for my tribe and adhere to this request.