[ImgBot] Optimize images

*Total -- 1,300.49kb -> 912.45kb (29.84%)

/images/ics-api-endpoints.png -- 40.65kb -> 24.42kb (39.92%)
/images/cas-api-endpoints.png -- 15.25kb -> 9.25kb (39.35%)
/images/google-architecture.png -- 395.75kb -> 266.95kb (32.55%)
/images/accounts-database-schema.png -- 848.84kb -> 611.83kb (27.92%)

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

Author: ImgBotApp