1. An image processing apparatus, comprising: a CPU programmed to: determine whether a feature amount in a partial region of an image satisfies a preset condition, select, from a plurality of images, a second image to be combined with a first image based on the result of the determination, detect a motion vector between the first image and the second image, and perform a composition process on the aligned first image and second image based on the motion vector, wherein, from the plurality of images, the CPU selects as the second image at least any one of an image having a partial region with the feature amount determined to satisfy the preset condition and an image corresponding to a partial region out of a plurality of partial regions set in the first image with the feature amount determined to satisfy the preset condition.