With the wide use of digital multimedia equipment, exchange of image data has become prevalent. Images and video data are exchanged through personal computers, mobile phones, and personal digital assistants (PDAs). Since the resolutions of each image display are different, it is necessary to change the image size accordingly. An image-resizing algorithm in the discrete cosine transform (DCT) domain is known to be fast for a compressed image. Most of the DCT domain methods truncate the high-frequency components during image downsampling and they are assumed to be zero to upsample images. We estimate the high-frequency parts using the correlation between the low- and the high-frequency components, and compare the peak SNR (PSNR) performances. We verify that the use of correlation is the best linear estimation in the mean square error sense.