This extension simply generates tiles of an image for "deep zooming."
Navigate to chrome://gen-tiles/content/generate.xul and select an image to
tile. The output directory will have files with names of the form:
  "tile_" + zoom_level + "_" + x_index + "_" + y_index + ".png"
where 0 is the zoom level at the highest resolution, x=0 is left and y=0 is top.

The generated tiles will be 256x256 pixels and in the PNG format.