[ImgBot] Optimize images

*Total -- 382.81kb -> 296.00kb (22.68%)

/imgs/screenshot.png -- 378.46kb -> 291.65kb (22.94%)
/imgs/favicon.svg -- 4.35kb -> 4.34kb (0.13%)

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

Author: ImgBotApp