If you're an image provider:
Once you've updated your visual content to include the appropriate information to potential users, you can use Google Search Console or the Rich Results tool to check everything is working ok. Google updated both tools to include testing options back in July. Google can't provide accurate license details unless providers update their content to provide that.
If you're an image user:
As the above screenshot shows, Google has begun to show a "Licensable" label in Google Image search results, making it far clearer what's usable and how to go the correct way about doing that.
When you click on an image with the label, you'll also get provided with a link to its license details, and another link to where you need to go to get that licence - but only if image owners provide those details.
What Google says:
Google says, "Finding the right image to use, and knowing how to use that image responsibly, isn't always a simple task. After collaborating closely with image creators, stock image providers and digital content associations, we're launching several new features on Google Images to address this need. We believe this is a step towards helping people better understand the nature of the content they're looking at on Google Images and how they can use it responsibly."