It gets the first image of a post and set it as the thumbnail and everything works fine on the front page except for my widgets. They do not seem to get the right url.
I checked to code of the plugin and they are doing something like:
I hope you are well today and thank you for your question.
It seems that plugin is not updated from last 2 years so could you please try using any of the following solutions to get the first image of a post and set it as the thumbnail.