Because you have an always sensor attached to the python script, youve got the script set to take a picture every millesecond or something like that.
do this:
keyboardsensor = cont.getSensor("keyboard sensor")
if keyboardsensor.isPositive:
Rasterizer.makeScreenshot("thingoname.jpg")
You should put a jpg extension on the end of the picture file name because i’ve otherwise experienced troubles opening the picture file.
… and for the background (skybox you mean?) thats not really possible or practical…
just open up the image into the blend file and go from there. opening up an image through python? nahhhhhhh…