In all previous Adventure Paths, the cover art was extractable from the PDF, at a size and resolution that was just about perfect for laptop wallpaper.
With Strange Aeons, unfortunately, this is not the case. The only extractable version of the cover art is the small version inset above the table of contents, which is fine for reading but too low-res to make nice wallpaper.
This makes me sad. I have always enjoyed collecting the covers of all the APs.
Is there any chance we could get updated versions of the PDFs with the cover images made separately extractable?
No, because what you're seeing is not a fault, nor an accident, nor a glitch. It's purposeful and intentional to prevent art theft.
Paizo's been locking down the art in all of it's works.. to the considerable consternation of folks trying to run these scenarios online or printing out decent size prints as opposed to trying to draw the maps.