Big Picture helps offload some longer-term lines off your chart so you can clutter it up again with some other stuff. It works by comparing SMAs 50 and 200 in histogram form. If the histogram is over the zero-line, 50 is over 200, and vice versa.
The histogram is green when the slope rises, suggesting that 50 is rising relative to 200. When the histogram turns red, 50 is falling.
Some Heikin-Ashi inspired averaging helps smooth the line just a little to help give a better idea as to overall trend.