The image display apparatus reads image data, which is recorded by a digital
camera etc., from a recording medium etc.; sets an in-focus frequency spectrum
threshold for in-focus determination according to the resolution (pixel count)
and compressibility of the inputted image data; analyzes a frequency spectrum of
the image data; and determines whether a location where frequency components whose
levels are higher than the threshold exist in an image. The location having the
most frequency components whose levels are higher than the threshold is determined
as an in-focus location. If an in-focus location exists, a mark showing the in-focus
location is displayed on a screen of a display device. If no in-focus location
exists in the image, the image display apparatus performs display of warning information
and/or a warning by sound, and prompts the user to confirm necessity of printing.
