The image that viewers may find most shocking is that of a baby being cut out of a woman's abdomen via c-section
主语:The image
that viewers may find most shocking是同位语从句修饰image
谓语:is
表语:that of a baby being cut out of a woman's abdomen via c-section这里的that 用来指代前面的the image,把句子恢复一下就是:The image is the image of a baby being cut out of a woman's abdomen via c-section 这样一来句子比较繁琐,所以在习惯上用that 代替后面的the image.就变成了that of a baby being cut out of a woman's abdomen via c-section.这里的of 是不能省略的,that 也不能省略的,都是句子的必要成分,这是一个很特殊的句型.