Thumbnails pixelated on frontpage

Hello there,
The thumbnails images generated by the widget News Show Pro on the frontpage looks pixelated. I putted a 240 x 240 px image size for the thumbnail in the widget configuration, the images uploaded are 900 x 900 px so should be ok. Is like the plugin resized them to a very low resolution. How can I fix it?
Thank you.

Hi,

Could you provide an URL to your website? (here or via PM)

Hello,
It was a silly thing, I fixed it just putting larger image dimensions on the widget configuration.
Thanks for your quick answer.