Table 1 Examples images before and after being shared and downloaded from social media platforms. The image size and the luminance quantization tables used for the last JPEG compression are reported in each case, showing notable differences between different versions

Native

Shared with Facebook

Shared with Flickr

Shared with Twitter

1920 × 2560

1536 × 2048

1536 × 2048

900 × 1200

\(\left [\begin {array}{cccccccc} 1&1&1&1&1&1&1&1\\ 1&1&1&1&1&1&1&1\\ 1&1&1&1&1&1&1&1\\ 1&1&1&1&1&1&1&1\\ 1&1&1&1&1&1&1&1\\ 1&1&1&1&1&1&1&1\\ 1&1&1&1&1&1&1&1\\ 1&1&1&1&1&1&1&1\\ \end {array}\right ]\)

\(\left [\begin {array}{cccccccc} 7& 5& 5& 7&11 & 18 & 23 & 28\\ 6& 6& 6& 9&12 & 27 & 28 & 25\\ 6& 6& 7 & 11 & 18 & 26 & 32 & 26\\ 6& 8&10 & 13 & 23 & 40 & 37 & 29\\ 8& 10 & 17 & 26 & 31 & 50 & 47 & 35\\ 11 & 16 & 25 & 29 & 37 & 48 & 52 & 42\\ 23 & 29 & 36 & 40 & 47 & 56 & 55 & 46\\ 33 & 42 & 44 & 45 & 52 & 46 & 47 & 46 \end {array}\right ]\)

\(\left [\begin {array}{cccccccc} 4 & 3 & 3 & 4 & 7 & 11 & 14 & 17\\ 3 & 3 & 4 & 6 & 7 & 17 & 17 & 15\\ 4 & 4 & 4 & 7 & 11 & 16 & 20 & 16\\ 4 & 5 & 6 & 8 & 14 & 25 & 22 & 17\\ 5 & 6 & 10 & 16 & 19 & 31 & 29 & 22\\ 7 & 10 & 15 & 18 & 23 & 29 & 32 & 26\\ 14 & 18 & 22 & 25 & 29 & 34 & 34 & 28\\ 20 & 26 & 27 & 28 & 32 & 28 & 29 & 28 \end {array}\right ]\)

\(\left [\begin {array}{cccccccc} 5 & 3 & 3 & 5 & 7 & 12 & 15 & 18\\ 4 & 4 & 4 & 6 & 8 & 17 & 18 & 17\\ 4 & 4 & 5 & 7 & 12 & 17 & 21 & 17\\ 4 & 5 & 7 & 9 & 15 & 26 & 24 & 19\\ 5 & 7 & 11 & 17 & 20 & 33 & 31 & 23\\ 7 & 11 & 17 & 19 & 24 & 31 & 34 & 28\\ 15 & 19 & 23 & 26 & 31 & 36 & 36 & 30\\ 22 & 28 & 29 & 29 & 34 & 30 & 31 & 30 \end {array}\right ]\)

Native

Shared with Whatsapp

Shared with Telegram

Shared with Messenger

1920 × 2560

1200 × 1600

1200 × 1600

1000 × 1334

\(\left [\begin {array}{cccccccc} 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1 \end {array}\right ]\)

\(\left [\begin {array}{cccccccc} 6 & 4 & 4 & 6 & 10 & 16 & 20 & 24\\ 5 & 5 & 6 & 8 & 10 & 23 & 24 & 22\\ 6 & 5 & 6 & 10 & 16 & 23 & 28 & 22\\ 6 & 7 & 9 & 12 & 20 & 35 & 32 & 25\\ 7 & 9 & 15 & 22 & 27 & 44 & 41 & 31\\ 10 & 14 & 22 & 26 & 32 & 42 & 45 & 37\\ 20 & 26 & 31 & 35 & 41 & 48 & 48 & 40\\ 29 & 37 & 38 & 39 & 45 & 40 & 41 & 40 \end {array}\right ]\)

\(\left [\begin {array}{cccccccc} 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1 \end {array}\right ]\)

\(\left [\begin {array}{cccccccc} 2 & 2 & 2 & 3 & 5 & 6 & 8 & 10\\ 2 & 2 & 2 & 3 & 5 & 6 & 8 & 10\\ 2 & 2 & 3 & 5 & 6 & 8 & 10 & 12\\ 3 & 3 & 5 & 6 & 8 & 10 & 12 & 14\\ 5 & 5 & 6 & 8 & 10 & 12 & 14 & 15\\ 6 & 6 & 8 & 10 & 12 & 14 & 15 & 15\\ 8 & 8 & 10 & 12 & 14 & 15 & 15 & 15\\ 10 & 10 & 12 & 14 & 15 & 15 & 15 & 15 \end {array}\right ]\)