1. An image processing apparatus comprising: determination means for determining whether a size of an outline vector to be output is not more than a predetermined size; and generation means for generating image data by using outline font data corresponding to the outline vector when said determination means determines that the size of the outline vector to be output is not more than the predetermined size, and generating image data by using the outline vector when said determination means determines that the size of the outline vector to be output is more than the predetermined size.