Fill with pattern

[maltje]

Hi I post it here because I can't post in gimp 2.10
I'm a newbie.
I open a new project
I draw a circle in it.
I fill this with a pattern ,everything ok.
Now I open a picture of let say a cross(downloaded from the internet.
I fill with a pattern but the filling is now black and white.
What do I wrong?

Kind regards