You're probably right that I shouldn't have been so rash, I'm sorry for the omission & my despondent attitude toward HEIC. My enthusiasm is sullied by the presence of royalties & a non-existent web presence because of these royalties which I consider reasonable (where JXL's lack of web presence is questionable). In the future, I may do a similar test and include HEIC, but currently I believe it fares worse than AVIF almost across the board. I'd be willing to see whether or not I'm correct in saying this, though.

I should include that under "Takeaway," I do say that " ... this is a non-scientific test," & it shouldn't be considered objective despite the use of metrics. While I find SSIMULACRA2 correlates very well with what my eyes see with these images & most other images, 27 landscape/architecture images aren't enough to draw any objective conclusions here & I'd need to do more testing in the future to produce research-quality work.