Hello stardepp,
My adivice, albeit too late, is always make backups
I'm sure its still ok to remove the line
<settings rotationPeriod="300" />, from the XML. and just leave the blank space, (unless someone knows different?).
Also, in the line of code that starts
<element type="Gallery", you just need to change
interval="60" to
interval="30", in order to have the artist pic change every 30 seconds.
Freddy