Very slowly loaded the pictures on the wordpress site?

Interested in such question,why the pictures loaded very slowly on the website? the picture weighing in at 40kb it takes 800мс reports from gmetrix and the result of 20картинок on the website 18сек total page load that is appalling!
Here is the report on gmetrix-

how to fix it?

https://gtmetrix.com/reports/ortusdental.ru/fB4vgwWJ