Featured image looks in low quality

We are testing the sparkling theme but we are strugling with the images quality issue.
Actually we have wordpress 4.7.4 but all the images we uploaded looks in a lower quality.

We have tried all the 2 solution above but nothing happens…
I don’t know if the problem been caused from the theme or comes from wordpress

The problem occured in all the website uploaded pictures

We prepare the images exactly for the destination so if the upload process reduce them the final result looks a shame

Hello there,

I hope you are doing well today.

The images actually look fine on my end.Please try clearing your WordPress cache with the following plugin:

Best Regards,
Support

Thanks for your prompt reply,

we have tried the suggested plugin, but didn’t solve the problem.
Attached a comparizon from the pictures on the top who comes from the blog and the one in the bottom who is the starting point before the upload.

As you can see in this case the quality is a little bit different. Looks like a little bit compressed somehow
Any idea?

Hello there,

Thanks for providing the image comparison.

Please try using the following optimization plugins to enhance the image quality. You would have to re-upload the images after activating the plugins, so the images would not be ignored by the plugins:

Best Regards,
Support