Hello Nsikanabasi,
Thanks for writing to us.
The Classic Recent Posts element has a fixed aspect ratio for the featured image It means you need to override the style of Classic Recent Posts element using custom CSS code to change the image size of the Posts featured image.
The featured image on Classic Recent Posts element is set as background-image, you can adjust its size by applying the background-size and height can be adjusted by increasing the padding-bottom CSS property.
I notice that the image of your 1st post is already cropped from the top. I would suggest you upload a larger size image to display properly.
You can also check this article to learn more about how to use browser inspector element.
You can find the proper CSS code selector using the Chrome browser Developer Toolbar.
Alternatively, You can use our bundled plugin called “The Grid” to display posts in the masonry grid with the featured image.
In case If you don’t know about how to display a post with the help of “The Grid” plugin please have a look at our The Grid plugin documentation.
Thanks