I myself use the iframe solution in my website:
example: <iframe width="100%" height="450" scrolling="no" allowfullscreen src="https://my-domain.com/vrview-master/index.html?image=https://my-domain.com/images/ANHD7535.jpg"></iframe>
testimage
indeed no way to zoom in and out, just navigate with mouse or finger.
I have read the google vr page so I make my 360° google spheres dimensions factor 2 ( 8192 x 4094)
also the viewer form Jérémy Heleine is very good:
http://jeremyheleine.me/#photo-sphere-viewer. I use that also. There you can zoom in and out.
Edited by: gvmelle on 18-Oct-2017 16:59