At least one processor of an electronic device is configured to: activate a first image sensor and a second image sensor; obtain first image data by means of the first image sensor; obtain second image data by means of the second image sensor; and determine to output a preview image on the basis of the first image data among the first image data and the second image data on a display. In response to the determination to output the preview image, the at least one processor is configured to: set the resolution of the first image data as a first resolution; and set the resolution of the second image data as a second resolution which is lower than the first resolution.