1. An image conversion method comprising: determining a number of frames to be used to convert a progressive image into an interlaced image; generating an interpolated image for the progressive image according to the determined number of frames; and converting the progressive image into an interlaced image using the interpolated image, wherein the determined number of frames is two, wherein the generating comprises: generating a first interpolated image for a first progressive image corresponding to a first frame, and generating a second interpolated image for a second progressive image corresponding to a second frame, and wherein the converting comprises: generating first and second interlaced images corresponding to first and second top fields, respectively, using the first and second interpolated images corresponding to the first and second frames, and generating a third interlaced image corresponding to a bottom field using the first and second interpolated images corresponding to the first and second frames.