In short, executing:
curl -v 'http://localhost:8096/emby/Items/337/Images/Primary?maxHeight=188&maxWidth=250&tag=b98cc27289a45fcbf1221e7cb04f8888&quality=90'
* processing: http://localhost:8096/emby/Items/337/Images/Primary?maxHeight=188&maxWidth=250&tag=b98cc27289a45fcbf1221e7cb04f8888&quality=90
* Trying [::1]:8096...
* Connected to localhost (::1) port 8096
> GET /emby/Items/337/Images/Primary?maxHeight=188&maxWidth=250&tag=b98cc27289a45fcbf1221e7cb04f8