[ImgBot] Optimize images

*Total -- 85.16kb -> 75.89kb (10.89%)

/demos/FilePicker/draganddrop.png -- 2.02kb -> 1.27kb (37.16%)
/demos/FilePicker/pickfromweb.png -- 2.53kb -> 1.70kb (32.72%)
/assets/css-social-buttons/site/white-radial-gradient.png -- 19.47kb -> 14.11kb (27.56%)
/demos/FilePicker/webcam.png -- 2.34kb -> 1.71kb (26.96%)
/demos/FilePicker/upload.png -- 1.24kb -> 1.03kb (16.55%)
/assets/logo.png -- 1.92kb -> 1.66kb (13.95%)
/assets/css-social-buttons/site/dingbat.png -- 0.70kb -> 0.64kb (8.29%)
/assets/css-social-buttons/site/button-sample.png -- 54.95kb -> 53.79kb (2.13%)

Author: ImgBotApp