250kb-500kb might be usable as a small thumbnail. 500kb-1mb usable up to A7 – one eighth of an A4 sheet (74 x 105 mm or 2⅞” x 4⅛”) 1mb-1.5mb up to A6 – one quarter of A4 (105 x 148 mm or 4 ⅛” x 5⅞”) 1.5mb – 2mb up to A5 – half A4 (148 x 210 mm or 5⅞” x 8¼”)