1. An image processing apparatus for generating a composite image, the apparatus comprising at least one processor to implement: a first low pass filter (LPF) configured to remove high-frequency components from first selection information about image data selection between a long-exposure image and a short-exposure image for each pixel of the composite image, thereby generating second selection information; a movement detector configured to obtain first movement detection information that identifies pixels corresponding to movement captured in at least one of the long-exposure image and the short-exposure image; a second LPF configured to remove high-frequency components from the first movement detection information, thereby generating second movement detection information; a selector configured to obtain selection results by exclusively selecting one of the first selection information and the second selection information for each pixel of the composite image based on the second movement detection information; and a composer configured to generate the composite image by combining the long-exposure image and the short-exposure image based on the selection results.