Help screenshots efficiency

A) Screenshots don't need alpha channels.
B) Can shave another ~10-15% or so by running pngout /f0 on everything. (http://www.advsys.net/ken/util/pngout.htm)

These are both lossless techniques.

Before: 2,526,235 bytes
After: 2,020,040 bytes
(including the diagrams, which did not need any recompression)

Here (assuming it attaches properly) is a tar of the images I recompressed.