[ImgBot] Optimize images

*Total -- 2,335.50kb -> 2,049.30kb (12.25%)

/task-1/task-1_screenshot.png -- 198.64kb -> 152.66kb (23.15%)
/task-5/Web_Screenshot_2.png -- 789.78kb -> 665.25kb (15.77%)
/task-5/Web_Screenshot.png -- 734.17kb -> 618.86kb (15.71%)
/task-5/bg.png -- 612.91kb -> 612.53kb (0.06%)

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

Author: ImgBotApp