[ImgBot] Optimize images

*Total -- 8,829.80kb -> 7,663.39kb (13.21%)

/screenshots/SRCNN.png -- 486.02kb -> 333.71kb (31.34%)
/Outputs/pepper.png -- 657.85kb -> 563.08kb (14.41%)
/Outputs/baby_GT.png -- 575.72kb -> 498.85kb (13.35%)
/Outputs/bird_GT.png -- 424.29kb -> 368.19kb (13.22%)
/Outputs/flowers.png -- 517.87kb -> 449.66kb (13.17%)
/Outputs/monarch.png -- 461.44kb -> 402.46kb (12.78%)
/Outputs/barbara.png -- 632.16kb -> 551.83kb (12.71%)
/Outputs/zebra.png -- 533.14kb -> 466.57kb (12.49%)
/Outputs/foreman.png -- 374.25kb -> 328.65kb (12.18%)
/Outputs/baboon.png -- 792.33kb -> 696.52kb (12.09%)
/Outputs/lenna.png -- 600.41kb -> 528.88kb (11.91%)
/Outputs/ppt3.png -- 434.43kb -> 382.69kb (11.91%)
/Outputs/woman_GT.png -- 418.40kb -> 371.71kb (11.16%)
/Outputs/head_GT.png -- 388.10kb -> 346.40kb (10.74%)
/Outputs/face.png -- 382.54kb -> 341.60kb (10.7%)
/Outputs/butterfly_GT.png -- 442.88kb -> 395.75kb (10.64%)
/Outputs/comic.png -- 620.07kb -> 555.14kb (10.47%)
/screenshots/screenshot.jpg -- 87.89kb -> 81.70kb (7.05%)

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

Author: ImgBotApp