Google Images has an option to filter images based on license.
Each image on my site has a details page, where I have the following link to denote the license:
<a rel="license" href="http://creativecommons.org/licenses/by/4.0/deed.en_US" target="_blank">CC-BY</a>
It's a modified version of the sample code from Creative Commons - Choose a License.
However, I see images that Google has indexed since I added this code do not appear when I select a license filter.
You need to wrap it around a div with an about attribute. Here's an example that Google provides:
<div about="image.jpg">
<img src="image.jpg" alt="" />
<a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/">Creative Commons Attribution Share-Alike 3.0</a>
</div>
So in your case:
<div about="image.jpg">
<img src="image.jpg" alt="" />
<a rel="license" href="http://creativecommons.org/licenses/by/4.0/deed.en_US" target="_blank">CC-BY</a>
</div>
Sources: https://www.youtube.com/watch?v=quyhasVn2jw, http://googlesystem.blogspot.com/2009/08/simple-way-to-specify-image-licenses.html
来源:https://stackoverflow.com/questions/22656219/how-do-i-set-the-license-for-images-on-my-site-in-google-images