Insert IMAGE into current buffer at point.
IMAGE is displayed by inserting STRING into the current buffer
with a `display' property whose value is the image. The default
STRING is a single space.
AREA is where to display the image. AREA nil or omitted means
display it in the text area, a value of `left-margin' means
display it in the left marginal area, a value of `right-margin'
means display it in the right marginal area.
The image is automatically split into ROWS x COLS slices.