Thumbnails not showing up

Hi,

I just installed this plugin and it works but the thumbnails are not showing up. I copied my feed url (it has the img tags into the desc) I selected to show description and to show thumbnails if present but it does not work neither, I also checked the html but there’s not img tags. What can I do? Any ideas? Any other plugin recommended?

Thanks

https://wordpress.org/plugins/super-rss-reader/