An image processing method comprising: a decoding processing step of applying decoding processing to a first kind of image data and a second kind of image data; a first resolution conversion processing step of applying first resolution conversion processing to the first kind of image data subjected to decoding processing; a parameter acquisition step of acquiring a parameter for resolution conversion of the second kind of image data subjected to decoding processing, on the basis of a result of the first resolution conversion processing; and a second resolution conversion processing step of applying a second resolution conversion processing to the second kind of image data subjected to decoding processing by using the acquired parameter.