1girl, absurdres, arms_behind_back, brown_eyes, covered_navel, gakuen_idolmaster, grey_hair, hair_tie_in_mouth, highres, idolmaster, long_hair, looking_at_viewer, mouth_hold, neckerchief, one-piece_swimsuit, ponytail, sailor_collar, school_uniform, serafuku, serasuku, shinosawa_hiro, sirotuki_ito, solo, swimsuit, swimsuit_under_clothes, thigh_gap