Delay loading images

Hello,

I found a problem about very delay loading images some page https://www.xn--12cfa7dloace9gwb4d2cfdb4juk8a0e.com/%e0%b9%81%e0%b8%9a%e0%b8%9a%e0%b8%9a%e0%b9%89%e0%b8%b2%e0%b8%99%e0%b8%99%e0%b9%87%e0%b8%ad%e0%b8%84%e0%b8%94%e0%b8%b2%e0%b8%a7%e0%b8%99%e0%b9%8c/ .

My site is running on VPS (RAM 8GB / CPU 4 cores / PHP 7.2) , WP V.5.2.4 and WP Fastest Cache Premium V 1.5.5

I enable all optimized (CSS, JS, Images) and clear cache but not working.

How to fix it?
I try to send request support via email but still not responds.
Please advised.

Thank you.
Thananit

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