I would like to present the image located on this website during a presentation I am giving next week. http://www.taopatch.com/blog/quantum-dots-entangled-with-single-photons/
The image does not say anything earthshattering, it is well accepted that the structure of a CdSe/CdS core-shell quantum dot is as they depict in the image, but the image does a great job of illustrating it. I do not believe the website was the original creator of the image, after all they refer to a certain paper that was published and in no way reference it. I believe this is the paper: doi:10.1038/nature11573 The image that they use is not in that paper.
edit: Here is another website containing the same image: http://en.rusnano.com/press-centre/news/88604
Can I present this image without knowing where it originally came from? I suppose I could cite the website as a source, but since it appears that they took the image without citing the original creators, I do not want to list them as the source.