If you follow the link: "If you would like to obtain permissions for the re-use or re-print of this image, please click here"
then you will see the name and source of the article. I find it quite annoying that they make this information purposefully obscure!
It looks like you need to have access to Springer images to see that. But since Springer would in fact benefit from you going to the original article if you have access to that (you might cite it after all), that might be an oversight. I would try to contact Springer and just ask them about that. Please update if you do get a reply from them.
It is indeed strange that such obvious information as the original reference is so hidden.