What is the optimum size of an image in EasyBlog so it is not vertically cut off in LinkedIn?

I want to start driving my LinkedIn connections to my EasyBlog posts. No matter what the size of the image PNG in the EasyBlog post, when I add the URL into the LinkedIn Share field, the image seems to re-size up, and the bottom of the image from the blog post gets cut off. How do I get the LinkedIn Share to display the full size image on the post? What I want to do seems to be done thousands of times a day by others, so I'm a bit flabbergasted. See attached.

Thanks in advance,
EdS