How to change border color on Picture Ring

I have an image on Picture Ring Control, and the borders are visible on any Style of controls. 

How can I remove/change them?

 In case of Picture Ring(NXG Style) you need to change the background color to "My VI" color and no borders would be visible.

1) Set the control on VI and from Advanced option choose Customize

2) From appeared space choose "Change to customize mode"

3) From Tools Pallet choose the color you want to have and save control

In result the borders will have same color as VI Background so they will become less visible/invisible if you use full colored  background.
 

You can find example VIs of edited controls attached below. 

Next Steps

For controls from other style palettes few more steps need to be done: 

1) As you can see, control consists of multiple parts: 

 2) Manipulation here is to minimize the "border" and put it inside of "inside container" keeping them both centralized (as shown in the picture below):