https://www.nature.com/articles/s41565-018-0337-2

$VersionNumber
ExampleData[{"TestImage", "Lena"}]
Out[]=11.2
Out[]= (* This output has been censored because the original 
 author Lena doesn't want her head chopped off and misused, but 
 apparently the call did still work in Version 11.2.  *)

Time for an upgrade?

Agree to retiring this image. I used it recently to test some image filters because my understanding was that Lena was a standard example used throughout the CS world. Not only was I wrong, I got in a bit of hot water. I assumed (sigh) the image must have been used because it had some unusual contrast or other photog features that made it a good test image. TIL the standard Lena pic is actually a PB image. Ugh.

Absolutely.

Relatively recent discussions on the Mathematica Stack Exchange Chat: https://chat.stackexchange.com/search?q=lena&room=2234. Unfortunately for some responding there is the "rationale" that if they aren't offended, then it's inconceivable that anyone else should be offended or that there can only be a very few that might be offended (and that those few just complain all the time anyway). Then there are those who insist that such examples remain because it has great historical value.

There's also a website devoted to retiring Lena: https://pursuit.unimelb.edu.au/articles/it-s-time-to-retire-lena-from-computer-science.

Finally, on the Mathematica Stack Exchange site, there are recent (November 2019) postings using Lena by extremely high reputation folks (some even being moderators): https://mathematica.stackexchange.com/search?tab=newest&q=lena.

So there is a long way to go.

A Google reverse image search restricted to wolfram.com finds three examples. Only one is in the current documentation: https://reference.wolfram.com/language/CUDALink/tutorial/Functions.html I could have sworn I've seen it elsewhere too in the docs but I can't find the references now.

Update: And ExampleData[{"TestImage", "Lena"}].