1. A method of processing an image within an image processing apparatus, the method comprising: receiving a command to convert the size of the image to a predetermined size; determining whether a subject in the image having the predetermined size is detectable; converting the size of the image according to the command; storing the image having the converted size; and outputting information indicating that a problem has occurred upon determining that the subject in the image having the converted size is undetectable while analyzing the image having the converted size.