Yay! Awesome work! I wanted to ask how you took the screenshots... but it's probably some mac functionality that windows doesn't have. 
In fact, it is
Macs have a built-in ability to take a screenshot of the whole screen, a selected rectangle, or a specific window, and dump it directly to a .png.
...though, in all fairness, I have been given to understand that more recent versions of Windows have less crippled screenshot functionality than XP and previous.
In any case, DF has its own image-dumping functionality, accessed from the [esc] menu (same place as where you save & quit). This simply dumps images of entire z-levels to .bmp files. On no account should one try to upload these .bmp files anywhere, however; they're absurdly large. DF comes bundled with a copy of optipng, which is a command-line tool that allows you to take the .bmp files and convert them into .png files of various sizes.
If you want to do any editing to the image dumps, though (cropping, annotating, etc), you should do it before converting, because MS Paint uses .bmp as a native format anyway, and it's non-lossy.
