With the latest update Zwift have fixed the functionality to upload screenshots to Strava.
At the end of a ride, just before you leave the End Ride window you have a option to select and upload up to 5 screenshots of your ride.
However because of some weird issue this function was broken for some time (and I mean a lot of time). So if you want to upload pictures of your Zwift ride, you need to add this manually in Strava. Not the best way, however this has been fixed.
So how does that look in Strava?
Well if you ask me this looks far better than just a picture of the map you have ridden.
With that ride on!