Loads the bitmap specified by the
filename input must be a word that is the name of valid bitmap file.
If the picture is small enough, it is pasted onto the screen such that its lower left corner is at the turtle's current position. Otherwise, the picture is positioned in the upper left corner of the screen. The picture is always pasted right-side-up with the bottom running horizontally and the sides running vertically, regardless of the turtle's orientation.
BITLOAD is equivalent to selecting the Bitmap - Load menu option.