Unter den Bildern... exactly what’s happening to die Bilder here? Is this now a masculine noun? “den” Bildern? Curious about adding the ‘n’ cchanging

Unter den Bildern… exactly what’s happening to die Bilder here? Is this now a masculine noun? “den” Bildern? Curious about adding the ‘n’
and seemingly changing the noun gender.

Hi, this is part of the German cases (declinations). This case is called „Dativ Plural“.
The gender never changes! :wink:

You can find an explanation here:

And here is a complete overview including plural and even adjectives:

Ja natürlich! Ich habe das komplett vergessen. Danke!