Image converter, image reproducer, image conversion/reproduction system, and recording medium

An image converter includes an image converting unit and a determining unit. The image converting unit acquires frame image groups each including one or more frame images from original image data, and outputs the frame image(s) of each acquired group, converting its/their image quality based on determination by the determining unit, generating foreign-device-use image data including the frame image groups including the frame image(s). The determining unit determines necessity of first-image-quality retention of the frame image(s) of each group based on whether it/they satisfies/satisfy a condition. The image converting unit outputs the frame image(s) of the group at the first image quality if it/they is/are determined by the determining unit as necessary to retain at the first image quality, or a second image quality if determined as unnecessary to retain at the first image quality.