Dialog or button Background Color ?

[Yad Bash-Bobby]

I'm building a desktop overlay with yad.  Using yad 5 times positioned by width, height, posx, posy to form a large display with 40 buttons.

Its there a way to remove the button box around image that is inside button ?

Or is their a way to change background color of yad dialog  or the background of button area ?

Included image is just a draft as finished product will be resized with smaller buttons with more distance between buttons. Maybe just icons with name below image.

Thanks for all help. 

[Yad Bash-Bobby]

I found a way to change the global GTK settings for window and button style but, this changes even the Desktop defaults as well. So if I change GTK window background in yad window, all system windows are blue background too. 

Is there a way to limit GTK window & button styles to just a particular yad dialog window ?