1girl, armpits, arms_up, breasts, crop_top, greyscale, hair_rings, kotoyama, looking_at_viewer, lying, monochrome, nanakusa_nazuna_(yofukashi_no_uta), on_back, short_hair, simple_background, sleeveless, sleeveless_turtleneck, smile, solo, turtleneck, white_background, yofukashi_no_uta