Greetings to the developers of this great plugin!
I have the same issue, therefore did not create a new thread, perhaps you can help me here.
I do not usually set a featured image to my posts. So, as instructed above, I have selected "The rich content" or "The full post" in "What type of text to display"
But it is picking the the image as full size and not cropping it to thumbnail size. Suppose if my image in the post was 900x900px the widget is showing the same size.
My question is how to make those images to fit the thumbnail size of lets say 96x96?