Create a simple combobox-style in WPF

Hey guys, I need somebody to quickly create a basic custom control style for me. What i need : Combobox that displays Images instead of text. I uploaded an example screenshot, my problem is that when adding an image I still have a white border and I can't manage to display the image in the combobox after selecting. Project : Create a new ComboBox-Control-Style that only displays the image after clicking without any borders and correctly displays the selected item.