I hope I'm not right
That's one of the reasons I started this thread - it does seem curious. I think the DX has better PDF support baked-in on purpose (textbooks), but to echo my original plea:
If anyone knows any tricks to get images in PDFs to display on the K2 without degradation, please chime in!
I've tried playing with image sizes, PDF settings, image DPI, etc etc etc to no avail thus far. Still far cruddier than in the Kindle image viewer.