The latest 360 Product Creator (build #71) outputs new version of the 360 viewer (#29), this is the new major feature:
Dynamic Image Resolution
The 360 Creator outputs a set of multiple resized image folders, not just two (or one) as before.
If the user is viewing the 360 view using a mobile device, or the targeting div is small, small images are loaded. When on fullscreen, or the targeting div is larger, images with higher resolution are used.
The new 360 viewer supports also retina screens now. This means on a retina device with (virtual) 320px screen width, images optimised for 640px viewer width are used.
These are the current image sizes, the 360 product creator and viewer are using: 360,750,1080,1500 and original hi-res images, based on this nice popular mobile screen resolutions blog post:
The WordPress plugin was also updated to reflect the new images directory structure.