Actually that is very difficult to cater this is because we can't control what image resolution user upload in EasySocial.

Imagine if the user upload this image resolution 1920x1080px, after it compressed, it will become following image resolution :
Thumbnail - 4xx - 2xx px
Large - 8xx - 4xx px

Another example image resolution 4xx x1000px, after it compressed, it will become following image resolution :
Thumbnail - 2xx - 5xx px
Large - 2xx - 6xx px

Even if we make it show 256 pixels from the Echo thumbnails container area, it also can't cater for all other image resolution, it will still appear image blurry.

I'm sorry to contradict you Arlex, but that's not what happens in practice.

No matter resolution of the original image, the resolution of the thumbnail is always 256 pixels (in height or width, depending on the original images).

Since the thumbnails are not always the same size according to the Joomla template, this confirms the need to have possibilities of media settings in the EasySocial backend.
To adjust resolution values of _large.jpg and _thumbnail.jpg images, according to the Joomla template used.
In this case, Echo template needs large images, for Covers and Thumbnails.

I stop bothering you, I'll let you work.
Good weekend Arlex !

Thanks for your input Philippe, we will see what we can do about this in the future.