A method of reproducing an image file from a recording medium that stores an image file of a first type and/or an image file of a second type includes reproducing the first type of image file or second type of image file, detecting whether each of a predetermined number of image files stored on the recording medium is the first type of image file or the second type of image file during the reproduction of an image file, and converting the second type of image file to the first type of image file by reading the main image data from the second type of image file, generating display-image data (image data for display use) based on the read main image data, and storing the generated display-image data in the original image file if the image file is determined to be the second type of image file based on the detection result. The first type of image file is an image file containing a header, main image data, and display-image data, and storing the display-image data in an area other than an area storing the header. The second type of image file is an image file containing a header and main image data, and storing no display-image data in an area other than an area storing the header. The image files of predetermined number being image files that can be reproduced when reproduction is done in the forward and/or reverse direction from the image file being reproduced.