I there a way to differenciate screen burn in and image retention?

[JD 96]

I have a Samsung S7 and noticed there was a faint ghosting from the notification bar. But I'm not sure if it's screen burn in or an image retention, since I've read that image retention goes away after a few days.
The phone is still under warranty, but our services are really bad, so I'd try to avoid that option if possible.

 

[Rukbat]

Image retention is screen burn-in.

 

[JD 96]

I read that image retention goes away after a few days, while burn in doesn't.