[ImgBot] Optimize images

*Total -- 70.82kb -> 56.23kb (20.6%)

/saves/v1/training_eval_loss.png -- 35.44kb -> 26.71kb (24.65%)
/saves/v1/training_loss.png -- 35.38kb -> 29.53kb (16.55%)

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

Author: ImgBotApp