If you want to create art, then create art. Don't pretend that automating a script is an artistic process when it's barely even engineering.
I don't know where you get your numbers buddy, but it takes me a 2-3 seconds per image on my PC.
To use your numbers, 2-3 seconds at a very conservative estimate of 400 watts is about 0.25 watt-hours, about 10,000 times more than the 0.000026Wh energy cost of a 4mb download.