Good work !
2 questions...

1 )
I've been trying to make a personal theme, using some existing files.
As you can see in the attached picture, I'd like the image viewer to show no borders around my pictures. But I get white strips around the big picture when the it is not zoomed enough.
Will you make this white background themable ?

2)
What will the webcam icon be there for ? (mb_viewer_camera.png)