[ImgBot] Optimize images

*Total -- 38.62kb -> 26.14kb (32.32%)

/sample.png -- 14.65kb -> 8.54kb (41.71%)
/dist/sample.png -- 14.65kb -> 8.54kb (41.71%)
/dist/icon.png -- 4.66kb -> 4.53kb (2.81%)
/icon.png -- 4.66kb -> 4.53kb (2.81%)

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

Author: ImgBotApp