featured image is very big on computers

I have a blog, for firts time a posted with featured image, on mobiles looks fine but in computers is horrible, pixelated and my photo inittialy had 2560x2560 px, now scale to 530x530 px and still the same.
You can see in: https://diwebpy.com/blog/

Hey there

Image size is for this blog archive is 750*500px, try to use images with this proportion

Hello, i change the image to 750x500, but i can’t see in my cell phone and in the computer is the same, you cant see in: https://diwebpy.com/blog/

Hi there

Featured image is not appearing even for desktop devices right now, please disable lazy load feature from the optimization plugin and check again

I want my site to be faster by adding Lazy Load but no plugin works, they all cause errors to occur in the Theme, what do you recommend for Lazy Load in illdy?

Hi there

You can still use Lazy load but try the different plugin, or use it without a CDN,
If you still struggling with this post your admin details and I will help you