The simplest and fastest scaling method is to arbitrarily retain one of every three scanlines, for example, retain the first and discard the others. This method is called sampling, and is specified by the keyword sample in the image region definition. It is easy to imagine the picture seriously deteriorating if a horizontal line representing a floor in the house is one of the scanlines discarded.

(If, instead, the image is a scanned representation of a picture of a house, the image is not likely to degrade significantly and the performance gain will be the stronger factor in choosing the scaling option.) sample is the default if you do not explicitly choose a scaling option and is the only method applicable to pseudo-colored images.