People always say that beautiful things are good, Or that "Beauty will save the world" as Dostoevsky said.

But... What about these?

One would call them morbid beauty, because death/destruction and beauty are intertwined in these images. Many of them do not even contain a speck of "good." Yet they are still beautiful.

People confuse beauty with goodness, forgetting that even death, killing, destruction, and evil can be beautiful.
Hannibal would be a great artistic example as to why beautiful is not equivalent to good.
Another example, one from the real life, is to watch any predator (a carnivore animal) during a hunt. They are absolutely beautiful and (not but) morbid.

ولقد ذكرْتُكِ والرِّماحُ نواهل
وبيْضُ الهِنْدِ تقْطرُ منْ دمي

فوددتُ تقبيل السيوفِ لأنها
لمعتْ كبارق ثغركِ المتبسِّم

لا تَغْتَرِرْ بنحُولِ خَصرٍ أهيَفِ
فالموتُ في حَدِّ الحُسامِ المُرهَفِ

Leonardo da Vinci understood this. He was a gentle soul for most of his life, but he also knew intuitively that beauty is not just a mysterious smile and a wild flower. He found it too in blood and guts while dissecting dead bodies, and designing military weapons. He discovered beauty in death and war too.