[ImgBot] optimizes images

*Total -- 484.41kb -> 464.44kb (4.12%)

/assets/images/cross_black@3x.png -- 0.68kb -> 0.53kb (21.92%)
/assets/images/rating-star@3.png -- 2.08kb -> 1.80kb (13.51%)
/assets/images/hamburger_menu@3x.png -- 0.54kb -> 0.47kb (12.36%)
/assets/images/cross_black@2x.png -- 0.45kb -> 0.42kb (6.94%)
/assets/images/background.jpg -- 384.73kb -> 367.72kb (4.42%)
/assets/images/riccardo-logo.png -- 95.93kb -> 93.49kb (2.54%)

Author: ImgBotApp