A non-transitory computer-readable storage medium stores instructions including first generating processing, first determination processing, second determination processing, second generating processing, and third determination processing for a terminal device with a camera. The first generating processing generates extracted image data from captured image data acquired by the camera. The first determination processing determines representative luminance values respectively representing luminances of the extracted image data. The second determination processing determines luminance correction values with respect to each of the plurality of extracted image data, based on a reference luminance value and the representative luminance values. The second generating processing generates composite image data from the extracted image data. The luminance of each extracted image data has been corrected using the luminance correction values. The third determination processing determines, based on the luminance correction values, an exposure correction value to correct an exposure of the camera.