[ImgBot] Optimize images

*Total -- 75.76kb -> 57.50kb (24.11%)

/screenshot.png -- 16.00kb -> 8.99kb (43.8%)
/images/theme_insert_here.png -- 14.94kb -> 9.85kb (34.06%)
/images/dracula_select.png -- 44.82kb -> 38.65kb (13.76%)

Signed-off-by: ImgBotApp <[email protected]>

Author: ImgBotApp