[ImgBot] Optimize images (#36)

*Total -- 399.73kb -> 279.15kb (30.17%)

/images/settings_ai.png -- 39.78kb -> 21.96kb (44.8%)
/images/settings_other.png -- 22.90kb -> 13.63kb (40.49%)
/images/settings_push.png -- 21.16kb -> 12.75kb (39.75%)
/images/settings_media.png -- 26.45kb -> 16.09kb (39.19%)
/images/settings_push_sub1.png -- 15.85kb -> 11.28kb (28.86%)
/images/settings_main.png -- 65.72kb -> 46.76kb (28.84%)
/images/settings_media_sub1.png -- 17.01kb -> 12.54kb (26.29%)
/images/flow_chart.png -- 172.55kb -> 128.87kb (25.31%)
/images/user_spy.png -- 18.32kb -> 15.28kb (16.57%)

Signed-off-by: ImgBotApp <ImgBotHelp@gmail.com>
Co-authored-by: ImgBotApp <ImgBotHelp@gmail.com>

Author: imgbot[bot]