To answer my questions and to help future:
Add to design > custom css
/* round image corners blog thumbnails */
.blog-basic-grid .image-wrapper {
border-radius: 100px 100px 5px 5px;
}
Site URL: https://www.postcardsfrompeta.com
I want to change my grid style blog page to show the featured posts/photos reshaped as an arched shape
Any help will be greatly appreciated.