Hi there - a workaround to hide the thumbnails on posts where you don't like the cropping would be to hide them using some CSS code.
You can add CSS through our Custom Design upgrade. An example of what the code would look like for the "Front Page Photo 3" is:
.post-215 .attachment-archive-thumbnail,
.post-215 .cat-links,
.post-215:hover a.read-more {
display: none;
}
You would repeat this block, editing the post ID as needed, for any other posts where you wanted to hide the thumbnails.
Just let me know if you need further help.