The function is called "Overview" in the English locale.
If you scroll with the mouse it will change the number of panels. Since the original aspect ratio is maintained it will only use perfect squares: 2x2, 3x3, 4x4, 5x5, 6x6, etc. The max is 10x10.
It's not currently possible to zoom or pan inside the images, get rid of the number, add analysis drawings or select the exact set of images you want to showcase. I agree it would be nice to have more options and be able to create a presentation using exactly the content you want. The main problem may be that the entire feature is only available when the player is in the special mode where the current section images are all cached in memory.