How to change the media player background picture

[HAuserSince2019]

I’m trying to do the same but seem to have stranded.

Change media.png accordingly for Denon mediaplayer

Boolean means two possible states. Typically false/ true, but yes/no, open/close 0/1 or even 0/any other value. If it is a boolean, then it does not make sense to use it like you do, but it could just be because you misunderstood the meaning of boolean and it is in fact another type of variable. If it is a string then it makes sense, but sometimes line breaks can mess things up, so try to use {{- and -}} instead. The minus will remove extra line break before or after respectively. Alsobtry …

When I Google I find only people with the same issue that the fuction in HA should work but it doesn’t. Have you managed it allready?