I have pics of the V1 shield at my website:http://www.chestersgarage.com
But the V2 shield isn't built yet and I haven't' figured out how people get those 3D renderings of their boards.
Analog dimming adjusts the brightness by changing the current flowing through the LED, as compared to PWM that switches the LED off and on very quickly. With analog dimming, you get light that does not flicker. So for projects such as a bicycle headlight where you are moving, you don't get the strobe light effect. (Think of the tail lights on a recent model luxury car) Analog dimming also provides the highest efficacy (aka efficiency) because LEDs give more light per watt at lower current levels. The trade-off is the LEDs will color-shift more with analog dimming than with PWM.
The additional manual analog dimming feature allows you to adjust the current through the LEDs, for example to balance color levels (RGB), set the maximum brightness for your needs, or prevent burning out the LEDs if the driver is rated higher than the LEDs.