[ImgBot] Optimize images

*Total -- 180.69kb -> 163.81kb (9.34%)

/images/example.jpg -- 180.10kb -> 163.25kb (9.36%)
/images/flags/USA-flag.png -- 0.59kb -> 0.57kb (4.6%)

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

Author: ImgBotApp