Graphic images are not an argument. They are an appeal to revulsion and emotion. Operation Rescue uses pictures of fetuses. PETA uses pictures of bullfights, and the slaughter of cattle and swine. "That looks gross" is not a moral or logical argument against eating meat, and it is not a moral or logical argument against abortion.
If you have to resort to gross-out pictures to make your case, it doesn't give the appearance of a strong case. Make the case rationally; no need to get vulgar and go into Larry Flynt territory.
The bloody images are PART OF the argument. They show the subject, in fact, and what separates a mere sophist from a true scholar is knowledge of the subject matter. The pro-abortion movement is built on sophistry - manipulation of words: murder becomes abortion; abortion becomes termination of pregnancy; termination of pregnancy becomes "choice". Their persuasion therefore rests on keeping true knowledge behind closed doors.
The First Amendment protects this speech, and since it is truth and not slander, it is perfectly legal. Beyond that, it is our moral obligation to future generations.
Graphic images cut through all the bs arguments put forth by pro-abort activists, legislators, executives and down the line. "That looks gross" is not the moral or logical argument against abortion being made by these displays. "That's a small baby chopped into pieces" is the moral and logical conclusion that any rational person would come to when seeing these images. You can describe the act all that you want but the images say a million words and the pro-abort crowd has no argument but denial, anger, and "gross" just for starters.
If only that was as far as it went. PETA frequently uses pictures of piles of corpses from concentration camps to equate carnivores with Nazis.
"That looks gross" is not a moral or logical argument against eating meat, and it is not a moral or logical argument against abortion.
When people eat chicken, they know they're eating a dead chicken. When people eat turkey, they know they're eating a dead turkey. When pro-choice people talk about "D & X" or "late term abortion" of a "fetus," they're pretending they aren't talking about a dead child, slaughtered as if it were a chicken or a turkey.
If billions of people around the world ate fetuses, it wouldn't be a moral or logical argument. But we don't. So it is.