Yeah, that was annoying to deal with when I posted because I would have to use Chrome's Dev tools to extract the image Url. For the average user, this wasn't so helpful if they didn't want ads.
So this means that there are a significant number of people "skilled" enough to right-click, but not skilled enough to view source. The mind boggles...
The latest variations of this put the transparent JPG in the source code, then load in the image via JS with a lower Z layer. Now you move from "View Source", to "Developer Extension, watch assets, copy initial URL, paste, save".
How is that at all surprising? Right click is a really common thing for most non-Mac users. View source is something most people have only used by accident.
I use a Mac every day. I also watch other people use Macs and not only do they not use a contextual menu, but they by and large don't use keyboard shortcuts either. HN users are a pretty small subset of computer users.