How to make website thumbnail not blurry?

Trouble with a blurred thumbnail at my website project

Greetings. Ladies And Gentleman I ask some question about this picture I've sent, what I want to ask about is how to make this picture's blurred thumbnail turned into High-Definition.

enter image description here

already try to turn off lazy loading with this code but loading="lazy"

add_filter( 'wp_lazy_loading_enabled', '__return_false' );

Website using Wordpress this is the link https://cloudteamize.com/test-porto/

Solution

THE SOLUTION IS FOUNDED:

the problem is the image link that my plugin using called: Portofolio Carousel is adding 350x181.png at the end of the link, I think that make my image use the lower quality.

example: the original file is -> mmd.png

but in that plugin -> mmd-350x181.png

i take the values of my src then remove the 350x150.png to only .png using my massy javascript like this:

$ = jQuery;
$(document).ready(function() {
    const imgs=document.querySelectorAll('#portofolio img');
    imgs.forEach(img => console.log(img.removeAttribute('srcset'), img.removeAttribute('loading'),img.src=img.src.replace("-350x181","")));
});

some how if I not doing my code inside console.log, the code didn't run. I think that is really weird, but some how when I try to put that in console.log, it just works so if you can give me suggestions or make this code clearer, that's will be great.