The only way to do it is by using the unique id of the homepage pane which currently resides in the uppermost section.
For example, this code will work for the current top pane (Test Post 6)…
#homepage-pane-83.homepage_pane img {
height: 200px;
}
However, when Test Post 4 moves up and takes the spot… the code above will no longer work. Because Test Post 4 is using a uniqe ID of homepage-pane-44
.
So basically, if you use this method… each time you publish a new post, you will need to go update that ID.