A display device includes a wavelet transform unit for transforming an original image into wavelet coefficients using a Harr wavelet transform formula, a level obtaining unit for obtaining a mipmap level of a mipmap image. The display device also includes an inverse wavelet transform unit for receiving and subjecting at least a portion of the wavelet coefficients obtained by the transformation by the wavelet transform unit, to an inverse transform using an inverse Harr wavelet transform formula until an order having a value equal to the mipmap level is obtained, and outputting an image represented by at least a portion of a low-frequency component of wavelet coefficients having the order having the value equal to the mipmap level. Additionally, the display device includes a polygon drawing unit for drawing the image output by the inverse wavelet transform unit, as a mipmap image, on the polygon image.