Image processing apparatus and storage medium

A non-temporary computer-readable storage medium storing an image processing program for processing picked-up images by a computer, the image processing program causing the computer to perform:

• a first synthesizing procedure for determining one out of a plurality of images as a reference image, determining a first synthesis ratio based on correlation amounts between the reference image and the plurality of images excluding the reference image and synthesizing a first image from the plurality of images based on the first synthesis ratio;
• a noise reducing procedure for reducing noise of at least the first image using a plurality of parameters and generating a plurality of noise-reduced images including at least a noise-reduced first image obtained as a result of reducing noise of the first image;
• and
• a second synthesizing procedure for determining a second synthesis ratio according to the first synthesis ratio and synthesizing a second image from the plurality of noise-reduced images based on the second synthesis ratio.